Ground DODGE RAM 1999 Service Manual PDF
[x] Cancel search | Manufacturer: DODGE, Model Year: 1999, Model line: RAM, Model: DODGE RAM 1999Pages: 1691, PDF Size: 40.34 MB
Page 314 of 1691
right kick panel. Disconnect CTM 18-pin connector C2. Turn ignition
on. Using an external voltmeter, measure voltage between ground and
CTM 18-pin connector C2 terminal No. 18 (Black/Red wire). If voltage
is more than 9.5 volts, replace CTM. If voltage is 9.5 volts or less,
repair open in Black/Red wire between CTM and horn relay.
6) Remove security relay from Power Distribution Center
(PDC). Turn ignition on. Connect a test light between battery source
and headlight relay connector terminal No. 85 (Red/Dark Blue wire).
Using scan tool, actuate relay. If test light illuminates, replace
security relay. If test light does not illuminate, go to next step.
7) Using an external voltmeter, measure voltage between
battery voltage and security relay connector terminal No. 86
(Red/Orange wire). If voltage is more than 9.5 volts, go to next step.\
If voltage is 9.5 volts or less, repair open in Red/Orange wire
between battery source and security relay.
8) Reinstall security relay. Locate Central Timer Module
(CTM). CTM is located behind right kick panel. Disconnect CTM 18-pin
connector C2. Using an external voltmeter, measure voltage between
ground and CTM 18-pin connector C2 terminal No. 6 (Red/Dark Blue
wire). If voltage is more than 9.5 volts, replace CTM. If voltage is
9.5 volts or less, repair open in Red/Dark Blue wire between CTM and
security relay.
9) Disconnect overhead console 12-pin connector. Using an
external voltmeter, measure voltage between battery and overhead
console 12-pin connector terminal No. 11 (Black wire). Using scan
tool, actuate VTSS indicator light. If voltage is about 10 volts,
replace overhead console. If voltage is not about 10 volts, go to next
step.
10) Measure voltage between ground and overhead console 12-
pin connector terminal No. 5 (Pink wire). Turn ignition on. If voltage\
is more than 10 volts, go to next step. If voltage is 10 volts or
less, repair open Pink wire.
11) Locate Central Timer Module (CTM). CTM is located behind\
right kick panel. Disconnect CTM 18-pin connector C2. Turn ignition
on. Using an external ohmmeter, measure resistance between ground and
CTM 18-pin connector C2 terminal No. 8 (Black wire). If resistance is
5 ohms or more, replace CTM. If resistance is less than 5 ohms, repair
open Black wire between CTM and VTSS indicator light.
12) Using scan tool, place VTSS in diagnostic mode and follow
directions on screen. If TURN KEY TO ACC POSITION is not displayed, go
to step 24). If NO RESPONSE after turning key to accessory position or
TURN KEY TO ACC POSITION is displayed longer than 15 seconds, go to
next step. If neither response is received, go to step 14).
13) Locate Central Timer Module (CTM). CTM is located behind\
right kick panel. Gain access to CTM 18-pin connector C2. Ensure key
is in accessory position. Using an external voltmeter, measure voltage
between ground and backprobe of CTM 18-pin connector C2 terminal No. 5
(Dark Blue/White wire). If voltage is more than 10 volts, replace CTM.\
If voltage is 10 volts or less, repair open Dark Blue/White wire
between CTM and junction block.
14) Remove key from ignition. Wait 2 seconds after performing
each of the following actions. Open, then close both door. Operate
power door lock switch to lock, then unlock position. Rotate key both
directions in both doors. Ensure each operation is successful. If any
operation is unsuccessful, see VTSS SYMPTOM DIRECTORY table for repair
of failed operation. If all operations are successful, go to step 22).
VTSS SYMPTOM DIRECTORY
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Problem Circuit Go To
Driver's Door Open Or Close ............................... Step 15)
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Passenger's Door Open Or Close ............................ Step 16)
Driver's Door Lock Switch ................. ONE OR ALL DOORS FAILING
TO LOCK FROM ONE SWITCH
Passenger's Door Lock Switch .............. ONE OR ALL DOORS FAILING
TO LOCK FROM ONE SWITCH
Driver's Key Cylinder ..................................... Step 17)
Passenger's Key Cylinder .................................. Step 20)
Driver's Door Unlock Switch ............... ONE OR ALL DOORS FAILING
TO UNLOCK FROM ONE SWITCH
Passenger's Door Unlock Switch ............ ONE OR ALL DOORS FAILING
TO UNLOCK FROM ONE SWITCH
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15) Ensure driver's door is closed. Using scan tool, read
VTSS inputs/outputs door ajar status. If scan tool displays DR DOOR
AJAR SWITCH: CLOSED, go to SHORTED LEFT DOOR AJAR CIRCUIT under DOOR
AJAR SYSTEM. If scan tool does not display DR DOOR AJAR SWITCH:
CLOSED, go to OPEN LEFT DOOR AJAR CIRCUIT under DOOR AJAR SYSTEM.
16) Ensure passenger's door is closed. Using scan tool, read
VTSS inputs/outputs door ajar status. If scan tool displays DR DOOR
AJAR SWITCH: CLOSED, go to SHORTED RIGHT DOOR AJAR CIRCUIT under DOOR
AJAR SYSTEM. If scan tool does not display DR DOOR AJAR SWITCH:
CLOSED, go to OPEN RIGHT DOOR AJAR CIRCUIT under DOOR AJAR SYSTEM.
17) Using scan tool, monitor door disarm switch state.
Disconnect left door disarm switch. Connect jumper wire between left
door disarm switch connector terminals. If scan tool displays door
disarm switch state CLOSED, replace left door disarm switch. If scan
tool does not display door disarm switch state CLOSED, go to next
step.
18) Disconnect jumper wire. Connect jumper wire between
ground and left door disarm switch connector Light Green/Orange wire.
If scan tool displays door disarm switch state CLOSED, go to next
step. If scan tool does not display door disarm switch state CLOSED,
repair open left door disarm switch ground circuit (Black/Light Green
wire).
19) Access Central Timer Module (CTM). CTM is located behind\
right kick panel. Remove connector cover. Do not disconnect connector.
Connect a jumper between ground and backprobe CTM 18-pin connector C2
terminal No. 10 (Light Green/Orange wire). If scan tool displays door
disarm switch state CLOSED, repair open left door disarm switch sense
circuit (Light Green/Orange wire). If scan tool does not display door
disarm switch state CLOSED, replace CTM.
20) Using scan tool, monitor door disarm switch state.
Disconnect right door disarm switch. Connect jumper wire between right
door disarm switch connector terminals. If scan tool displays door
disarm switch state CLOSED, replace right door disarm switch. If scan
tool does not display door disarm switch state CLOSED, go to next
step.
21) Disconnect jumper wire. Connect jumper wire between
ground and right door disarm switch connector Light Green/Orange wire.
If scan tool displays door disarm switch state CLOSED, go to next
step. If scan tool does not display door disarm switch state CLOSED,
repair open right door disarm switch ground circuit (Black/Light Green
wire).
22) Access Central Timer Module (CTM). CTM is located behind\
right kick panel. Remove connector cover. Do not disconnect connector.
Connect a jumper between ground and backprobe CTM 18-pin connector C2
terminal No. 10 (Light Green/Orange wire). If scan tool displays door
disarm switch state CLOSED, repair open right door disarm switch sense
circuit (Light Green/Orange wire). If scan tool does not display door
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disarm switch state CLOSED, replace CTM.
23) Turn ignition switch to START position. If horn does not
sound, go to next step. If horn sounds, go to step 24).
24) Locate Central Timer Module (CTM). CTM is located behind\
right kick panel. Disconnect CTM 14-pin connector C1. Using an
external voltmeter, measure voltage between ground and CTM 14-pin
connector C1 terminal No. 8 (Dark Blue/White wire). If voltage is more\
than 10 volts, replace CTM. If voltage is 10 volts or less, repair
open Dark Blue/White wire between CTM and RUN-ACC fuse in junction
block.
WINDSHIELD WIPER SYSTEM
WIPER PARK SWITCH FAILURE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting or connecting any module connector.
NOTE: It takes 8 seconds for wiper park switch failure DTC to set.
1) Using scan tool, clear DTCs. See appropriate SELF-
DIAGNOSTICS article. Operate wipers in low speed, then intermittent
mode. Reread DTCs. If WIPER PARK SWITCH FAILURE is displayed, go to
next step. If WIPER PARK SWITCH FAILURE is not displayed, system is
currently functioning properly.
2) Gain access to wiper motor connector. Using an external
voltmeter, measure voltage between ground and wiper motor terminal No.
2 (Dark Green wire). If voltage is more than 9 volts, go to next step.\
If voltage is 9 volts or less, replace wiper motor.
3) Locate Central Timer Module (CTM). CTM is located under
left side of instrument panel. Using an external voltmeter, measure
voltage between ground and backprobe of CTM 14-pin Green connector C1
terminal No. 11 (Dark Green wire). If voltage is 9 volts or less,
replace CTM. If voltage is more than 9 volts, repair short to voltage
in Dark Green wire between CTM and wiper relay or wiper motor.
INTERMITTENT WIPERS INOPERATIVE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting or connecting any module connector.
1) Using scan tool select CENTRAL TIMER MODULE. If scan tool
displays NO RESPONSE, go to appropriate VEHICLE COMMUNICATIONS
article. If scan tool displays any CCD bus failure message, go to
SYMPTOM IDENTIFICATION. If scan tool does not display NO RESPONSE or
any CCD bus failure message, go to next step.
2) If problem is wipers parking in wrong position, go to next
step. If problem is not wipers parking in wrong position, go to step
5).
3) Gain access to wiper motor connector. Turn wipers on to
low speed. Using an external voltmeter, measure voltage between ground
and wiper motor switch terminal No. 2 (Dark Green wire). If voltage
does not cycle between zero and 12 volts, replace wiper motor. If
voltage cycles between zero and 12 volts, go to next step.
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4) Locate Central Timer Module (CTM). CTM is located under
left side of instrument panel. Using an external voltmeter, measure
voltage between ground and backprobe of CTM 14-pin Green connector C1
terminal No. 11 (Dark Green wire). Wipers should be operating at low
speed. If voltage does not cycle between zero and 12 volts, repair
open Dark Green wire between CTM and wiper relay or wiper motor. If
voltage cycles between zero and 10 volts, replace CTM.
5) Using scan tool, monitor intermittent wiper voltage level.
Rotate wiper switch from low intermittent to high intermittent level.
If voltage changes from approximately 2.5 to 12 volts, replace CTM. If
voltage does not change from approximately 2.5 to 12 volts, go to next
step.
6) Disconnect 24-pin multifunction switch connector. Using an
external ohmmeter, measure resistance of White/Dark Blue wire between
multifunction switch connector terminal No. 1 and CTM 14-pin Green
connector C1 terminal No. 12. if resistance is less than 5 ohms,
replace multifunction switch. If resistance is 5 ohms or more, repair
open White/Dark Blue wire between multifunction switch and CTM.
NO WIPER ACTUATION AFTER WASH BUTTON PUSHED
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting or connecting any module connector.
1) Using scan tool select Central Timer Module (CTM). If sca\
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tool displays NO RESPONSE, go to appropriate VEHICLE COMMUNICATIONS
article. If scan tool displays any CCD bus failure message, go to
SYMPTOM IDENTIFICATION. If scan tool does not display NO RESPONSE or
any CCD bus failure message, go to next step.
2) Turn ignition on. If washer system works, go to next step.
If washer system does not work, see appropriate WIPER/WASHER SYSTEMS
article.
3) Using scan tool, actuate washer. If washer pump sense
displays ON, replace CTM. If washer pump sense does not display ON,
repair open Brown wire between CTM 14-pin connector C1 terminal No. 10
and multifunction switch.
WIPER SPEED SENSITIVE FEATURE INOPERATIVE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1A after each repair.
CAUTION: Always turn ignition switch to OFF position prior to
disconnecting or connecting any module connector.
1) Using scan tool select Central timer module (CTM). If sca\
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tool display is not blank or have a CCD bus failure message, go to
next step. If scan tool display is blank or has a CCD bus failure
message, see appropriate VEHICLE COMMUNICATIONS article.
2) Using scan tool, select Powertrain Control Module (PCM).
If scan tool display is not blank or have a CCD bus failure message,
go to next step. If scan tool display is blank or has a CCD bus
failure message, see appropriate VEHICLE COMMUNICATIONS article.
3) Raise and support vehicle. Turn wipers on to lowest
intermittent position. Time interval between wipes. Spin rear wheels
to more than 15 MPH. If interval between wipes decreased to
approximately 18 seconds, system is currently functioning properly. If
interval between wipes did not decrease to approximately 18 seconds,
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and make an informed decision about how to proceed.
BRAKES
SERVICE PROCEDURES REQUIRED & SUGGESTED FOR PROPER
VEHICLE OPERATION
Some states may have specifications that differ from OEM.
Check your local/state regulations. Where state or local laws are
stricter, they take precedence over these guidelines.
ACCELEROMETERS (G SENSOR OR LATERAL)
ACCELEROMETER INSPECTION \
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Condition Code Procedure
Broken .................. A ............ Require replacement.
Connector loose ......... A .. Require repair or replacement.
Loose ................... B .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Out of position ......... B ....... Require re-positioning to
vehicle manufacturer's
specifications.
Output signal incorrect . B ............ Require replacement.
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ACCUMULATORS
ACCUMULATOR INSPECTION \
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Condition Code Procedure
Leaking ................. B ............ Require replacement.
Missing ................. C ............ Require replacement.
Pre-charge incorrect .... B ............ Require replacement.
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ANCHOR PINS
See BACKING PLATES .
ANTI-LOCK BRAKE SYSTEMS
NOTE: Anti-lock brakes are an integral part of the brake system. It
is essential that the anti-lock brakes function properly when
brake service is performed.
Anti-lock brake systems are commonly referred to as "ABS" and
will be referred to as "ABS" throughout these guidelines. Some ABS
components also function as part of a traction control system (TCS).
WARNING: When diagnosing and servicing high pressure components,
observe safety procedures and equipment requirements
established by the vehicle manufacturer to reduce the
possibility of serious personal injury.
NOTE: Intermittent electrical conditions are often caused by a loss
of ground, poor connection, or water intrusion into the
wiring harness.
Page 385 of 1691
operator's foot off accelerator pedal, S/C compensates for excessive
S/C cable slack. If lift foot sets are continually used, speed control
overshoot/undershoot condition will develop.
To "unlearn" overshoot/undershoot condition, operator must
press and release set button while maintaining desired speed with
accelerator pedal, then turn S/C switch to OFF position after waiting
10 seconds. This procedure must be repeated 10-15 times to completely
unlearn overshoot/undershoot condition.
COMPONENT TESTS
WARNING: Vehicle is equipped with an air bag. Air bag must be
deactivated before servicing speed control components on or
around steering column. See appropriate AIR BAG RESTRAINT
SYSTEMS article.
NOTE: For component locations, See COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
BRAKE SWITCH
Disconnect brake switch 6-pin connector. Using an ohmmeter,
check for continuity at brake switch. See Fig. 1. If continuity is not
as specified in BRAKE SWITCH CONTINUITY table, check brake switch
adjustment. See BRAKE SWITCH under REMOVAL & INSTALLATION. If brake
switch adjustment is okay, replace defective brake switch.
BRAKE SWITCH CONTINUITY
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Switch Plunger Check Between Continuity
Position Terminals
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Released 5 & 6 Yes
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Depressed 1 & 2 Yes
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3 & 4 Yes
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SPEED CONTROL SERVO
1) Start engine. Disconnect Speed Control (S/C) servo 4-pin
connector. Turn S/C on. Using a voltmeter, check voltage at S/C servo
connector terminal No. 3 (Dark Blue/Red wire). Battery voltage should
exist when brake pedal is not depressed. If battery voltage exists, go
to next step. If battery voltage does not exist, check circuit between
brake switch and S/C servo. See WIRING DIAGRAMS.
2) Connect a jumper wire between S/C servo pin No. 3 and S/C
servo connector terminal No. 3. Check voltage at S/C servo pins No. 1,
2 and 4. If battery voltage does not exist, replace S/C servo. If
battery voltage exists, go to next step.
3) Turn ignition off. Check for continuity between S/C servo
connector terminal No. 4 and ground. If continuity exists, test is
complete. If continuity does not exist, repair open ground circuit as
necessary.
VACUUM SUPPLY
Gasoline Engines
1) Disconnect vacuum hose at speed control servo. Install
vacuum gauge to disconnected vacuum hose. Start engine and observe
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made.
* When using a jumper wire, ensure either jumper wire or
circuit is fuse-protected.
* Before disconnecting connector from any control module,
ensure ignition is off before removing connector.
* When checking voltage or continuity at any control module,
probe connector for control module from pin side. DO NOT
backprobe connector or probe wires through insulation.
* DO NOT cause short circuits when performing electrical tests.
This will set additional Diagnostic Trouble Codes (DTCs),
making diagnosis of original problem more difficult.
* Use specified test equipment when performing electrical
tests.
RETRIEVING DIAGNOSTIC TROUBLE CODES
NOTE: Self-diagnostic tests are written specifically for Chrysler's
Diagnostic Readout Box (DRB). If using a generic scan tool,
ensure it is OBD-II certified. A generic scan tool may not be
capable of performing all necessary test functions.
Ensure battery is fully charged. Turn ignition off. Connect
scan tool to Data Link Connector (DLC). DLC is located under left side\
of instrument panel. Turn ignition on. Using scan tool manufacturer's
instructions, record all DTCs displayed on scan tool. If ant DTCs are
retrieved, perform appropriate test under DIAGNOSTIC TESTS. Once all
repairs are made, clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES.
If no DTCs are retrieved and fault still exists, go to CHECKING SPEED
CONTROL OPERATION under SYSTEM TESTS.
CLEARING DIAGNOSTIC TROUBLE CODES
Ensure ignition is off. Connect scan tool to DLC. Turn
ignition on. Using screen prompts on scan tool, erase DTCs from PCM.
DIAGNOSTIC TESTS
FTC P0720: LOW OUTPUT SPEED SENSOR (OSS) RPM MORE THAN 15 MPH
FTC P0720 will set if output shaft speed is less than 60 RPM
for 2.6 seconds when vehicle speed is more than 15 MPH.
Possible Causes:
* Defective Output Speed Sensor (OSS).
* OSS signal circuit open or shorted.
* OSS ground circuit open or shorted.
* Park/Neutral Position (PNP) switch FTC present.
* Defective PNP switch.
* Defective PCM.
1) Turn ignition on. Using scan tool, read DTCs. If FTC
specific good trip is displayed and equal to zero, go to next step. If
FTC specific good trip is equal to more than zero, go to step 13).
2) If there are any Park/Neutral Position (PNP) switch DTCs,\
repair PNP switch FTC first. Perform TEST VER-5A under VERIFICATION
TESTS. If there are no PNP switch DTCs, go to next step.
3) Using scan tool, read PNP switch state. While observing
scan tool, shift transmission through all positions. If scan tool did
not display P/N and D/R in correct positions, repair PNP switch or
circuit as necessary. Perform TEST VER-5A under VERIFICATION TESTS. If
Page 390 of 1691
scan tool displayed P/N and D/R in correct positions, go to next step.
4) Raise drive wheels and support vehicle, allowing wheels to
spin. Using scan tool, erase DTCs. Start engine. Using scan tool, read
Output Speed Sensor (OSS). Shift transmission into first gear. While
observing scan tool, allow wheels to spin at a speed less than 15 MPH.
If scan tool displays OSS more than 60 RPM, go to next step. If scan
tool displays OSS 60 RPM or less, go to step 7).
5) While wheels are spinning, wiggle wiring between OSS and
PCM. If OSS reading dropped while wiggling, repair intermittent short
or open circuit. Perform TEST VER-5A under VERIFICATION TESTS. If OSS
reading did not drop, go to next step.
6) Using scan tool, erase DTCs. Road test vehicle. Read DTCs.
If FTC P0720 returns, replace PCM. Perform TEST VER-5A under
VERIFICATION TESTS. If FTC P0720 did not return, go to step 13).
7) Turn ignition off. Disconnect PCM. Inspect connectors.
Clean or repair as necessary. Using an ohmmeter, measure resistance
between ground and OSS signal circuit at PCM connector C2, terminal
No. 28 (Light Green/Black wire on Ram Pickup; Light Green/White wire
on all other models). If resistance is less than 5 ohms, repair short
to ground. Perform TEST VER-5A under VERIFICATION TESTS.
8) Using an ohmmeter, measure resistance between ground and
OSS ground circuit at PCM connector C2, terminal No. 25 (Dark
Blue/Black wire). If resistance is less than 5 ohms, repair short to
ground. Perform TEST VER-5A under VERIFICATION TESTS. If resistance is
5 ohms or more, go to next step.
9) Disconnect OSS. Using an ohmmeter, measure resistance
across OSS terminals. If resistance is not 300-1200 ohms, replace OSS.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is 300-
1200 ohms, go to next step.
10) Using an ohmmeter, measure resistance of OSS signal
circuit between PCM connector C2, terminal No. 28 and OSS connector
(Light Green/Black wire on Ram Pickup; Light Green/White wire on all
other models). If resistance is more than 5 ohms, repair open circuit.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is 5 ohms
or less, go to next step.
11) Using an ohmmeter, measure resistance of OSS ground
circuit between PCM connector C2, terminal No. 25 and OSS connector
(Dark Blue/Black wire). If resistance is more than 5 ohms, repair open\
circuit. Perform TEST VER-5A under VERIFICATION TESTS. If resistance
is 5 ohms or less, go to next step.
12) Reconnect OSS. Using an ohmmeter, measure resistance
between PCM connector C2, terminals No. 25 (Dark Blue/Black wire) and
No. 28 (Light Green/Black wire on Ram Pickup; Light Green/White wire
on all other models). If resistance is 300-1200 ohms, replace PCM.
Perform TEST VER-5A under VERIFICATION TESTS. If resistance is not
300-1200 ohms, go to next step.
13) Inspect wiring and connectors. repair as necessary.
Perform TEST VER-5A under VERIFICATION TESTS. If wiring and connectors
are okay, go to next step.
14) Conditions required to set FTC are not present at this
time. Check freeze frame data to determine conditions when FTC was
set. Raise drive wheels and support vehicle, allowing wheels to spin.
Using scan tool, read OSS. Shift transmission into first gear. While
observing scan tool, allow wheels to spin at a speed less than 15 MPH.
Wiggle wiring between OSS and PCM. If OSS reading dropped while
wiggling, repair intermittent short or open circuit. Perform TEST VER-
5A under VERIFICATION TESTS. If OSS reading did not drop, no problem
is indicated at this time.
FTC P1595: SPEED CONTROL SOLENOID CIRCUITS
Speed Control (S/C) solenoid circuits are monitored when
engine is running, S/C switch is on and battery voltage is more than
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10.4 volts. FTC P1595 will set if vacuum and vent solenoids do not
respond when actuated by PCM.
Possible Causes:
* Ground circuit open.
* S/C brake switch output circuit open.
* S/C power supply circuit open or shorted.
* S/C servo defective.
* S/C vacuum solenoid control circuit open or shorted.
* S/C vent solenoid control circuit open or shorted.
* Brake switch defective or out of adjustment.
* Defective PCM.
NOTE: For component locations, see COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR
IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS.
1) Turn ignition on. Turn Speed Control (S/C) on. Using scan\
tool, actuate S/C vent solenoid. If speed control servo clicks, go to
next step. If S/C servo does not click, go to step 7).
2) Using scan tool, actuate S/C vacuum solenoid. If S/C servo
clicks, go to next step. If S/C servo does not click, go to step 6).
3) Turn ignition on. Using scan tool, actuate S/C vacuum
solenoid. Wiggle wiring harness between S/C servo and brake switch to
PCM while scan tool is still actuating speed control vacuum solenoid.
If wiggling did not cause an interruption of S/C servo actuation, go
to next step. If wiggling caused an interruption of S/C servo
actuation, repair wiring harness as necessary. Perform TEST VER-4A
under VERIFICATION TESTS.
4) Turn ignition off. Inspect S/C wiring and connectors.
Clean or repair as necessary. Perform TEST VER-4A under VERIFICATION
TESTS. If wiring and connectors are okay, go to next step.
5) Using scan tool, actuate S/C vent solenoid. Wiggle wiring
harness between S/C servo and brake switch to PCM while scan tool is
still actuating speed control vacuum solenoid. If wiggling did not
cause interruption of S/C servo actuation, test is complete. If
wiggling caused interruption of S/C servo actuation, repair wiring
harness as necessary. Perform TEST VER-4A under VERIFICATION TESTS.
6) Using scan tool, actuate S/C vent solenoid. Wiggle wiring
harness between S/C servo and brake switch to PCM while scan tool is
still actuating speed control vacuum solenoid. If wiggling did not
cause interruption of S/C servo actuation, go to next step. If
wiggling caused interruption of S/C servo actuation, repair wiring
harness as necessary. Perform TEST VER-4A under VERIFICATION TESTS.
NOTE: Ensure brake pedal is not depressed during the following
steps.
7) Turn ignition off. Disconnect S/C servo 4-pin connector.
Inspect all related wiring and connectors and repair as necessary.
Turn ignition on. Turn S/C switch on. Using a 12-volt test light,
probe brake switch output circuit at S/C servo connector terminal No.
3 (Dark Blue/Red wire). If test light is illuminated and bright, go to\
next step. If test light is dim or not illuminated, go to step 13).
8) Turn ignition off. Using an ohmmeter, check resistance of
ground circuit at S/C servo connector terminal No. 4 (Black wire). If
resistance is 5 ohms or more, repair open ground circuit. Perform TEST
VER-4A under VERIFICATION TESTS. If resistance is less than 5 ohms, go
to next step.
9) Disconnect PCM. Inspect connectors. Clean or repair as
necessary. Using an ohmmeter, measure resistance between ground and
S/C vacuum solenoid control circuit at S/C servo connector terminal
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No. 1 (Tan/Red wire). If resistance is less than 5 ohms, repair short
to ground. Perform TEST VER-4A under VERIFICATION TESTS. If resistance
is 5 ohms or more, go to next step.
10) Using an ohmmeter, check resistance between ground and
S/C vent solenoid control circuit at S/C servo connector terminal No.
2 (Light Green/Red wire). If resistance is less than 5 ohms, repair
short to ground. Perform TEST VER-4A under VERIFICATION TESTS. If
resistance is 5 ohms or more, go to next step.
11) Using an ohmmeter, measure resistance of S/C vacuum
solenoid control circuit between S/C servo connector terminal No. 1
and PCM connector C3, terminal No. 4 (Tan/Red wire). If resistance is
5 ohms or more, repair open circuit. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is less than 5 ohms, go to next
step.
12) Using an ohmmeter, check resistance of S/C vent solenoid
control circuit between S/C servo connector terminal No. 2 and PCM
connector C3, terminal No. 5 (Light Green/Red wire). If resistance is
5 ohms or more, repair open circuit. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is less than 5 ohms, replace S/C
servo. Perform TEST VER-4A under VERIFICATION TESTS.
13) Using an ohmmeter, check resistance between ground and
brake switch output circuit at S/C servo connector terminal No. 3
(Dark Blue/Red wire). If resistance is less than 5 ohms, repair short
to ground. Perform TEST VER-4A under VERIFICATION TESTS. If resistance
is 5 ohms or more, go to next step.
14) Reconnect PCM. Disconnect brake switch connector. Turn
ignition on. Turn S/C on. Using a 12-volt test light, probe S/C power
supply circuit at brake switch connector terminal No. 3 (Yellow/Red
wire). If test light is illuminated and bright, go to next step. If
test light is not illuminated or dim, go to step 17).
15) Turn ignition off. Using an ohmmeter, check resistance of
S/C brake switch output circuit between S/C servo connector terminal
No. 3 and brake switch connector terminal No. 4 (Dark Blue/Red wire).
If resistance is 5 ohms or more, repair open circuit. Perform TEST
VER-4A under VERIFICATION TESTS. If resistance is less than 5 ohms, go
to next step.
16) Check brake switch adjustment. See BRAKE SWITCH under
REMOVAL & INSTALLATION. Adjust as necessary. Perform TEST VER- 4A
under VERIFICATION TESTS. If brake switch adjustment is okay, replace
brake switch. Perform TEST VER-4A under VERIFICATION TESTS.
17) Turn ignition off. Disconnect PCM. Inspect connectors.
Clean or repair as necessary. Using an ohmmeter, measure resistance of
S/C power supply circuit between PCM connector C3, terminal No. 11 and
brake switch connector terminal No. 3 (Yellow/Red wire). If resistance\
is 5 ohms or more, repair open circuit. Perform TEST VER-4A under
VERIFICATION TESTS. If resistance is less than 5 ohms, replace PCM.
Perform TEST VER-4A under VERIFICATION TESTS.
FTC P1596: SPEED CONTROL SWITCH ALWAYS HIGH
FTC P1596 will set if an open circuit is detected in Speed
Control (S/C) switch circuit when ignition is on.
Possible Causes:
* Defective clockspring.
* S/C switch ground circuit open.
* Defective ON/OFF switch.
* Defective PCM.
* S/C switch signal circuit open or shorted to voltage.
NOTE: For component locations, see COMPONENT LOCATIONS. For
connector terminal identification, see CONNECTOR