display DODGE RAM 1999 Service Manual PDF

If equipped, the EMR light (some models may use a reminder
flag) reminds vehicle operator that an emission system maintenance is
required. This indicator is activated after a predetermined
time/mileage.
When performing a smog check inspection, ensure EMR indicator
is not activated. On models using an EMR light, light should glow when
ignition switch is turned to ON position and should turn off when
engine is running.
If an EMR flag is present or an EMR light stays on with
engine running, fail vehicle and service or replace applicable
emission-related components. To reset an EMR indicator, refer to
appropriate MAINTENANCE REMINDER LIGHTS in the MAINTENANCE section.
MALFUNCTION INDICATOR LIGHT (MIL)
The Malfunction Indicator Light (MIL) is used to alert
vehicle operator that the computerized engine control system has
detected a malfunction (when it stays on all the time with engine
running). On some models, the MIL may also be used to display trouble
codes.
As a bulb and system check, malfunction indicator light will
glow when ignition switch is turned to ON position and engine is not
running. When engine is started, light should go out.


IN STR UM EN T P A N EL - A N ALO G

1999 D odge P ic ku p R 1500
1999 ACCESSORIES & EQUIPMENT
CHRY - Analog Instrument Panels
Ram Pickup, Ram Van & Ram Wagon
DESCRIPTION & OPERATION
INSTRUMENT CLUSTER
All instrument cluster gauges are air core magnetic type.
Tachometer is optional. All gauges use data transferred on Chrysler
Collision Detection (CCD) bus. Instrument cluster incorporates a
Vacuum Fluorescent Display (VFD) for odometer display.
Brake warning light illuminates when ignition is on and
parking brake is applied. Brake warning light also illuminates if
brake hydraulic system failure occurs during service brake
application. Brake warning light bulb test occurs when ignition switch
is in START position.
Oil pressure warning light illuminates when engine oil
pressure is not sufficient to open oil pressure sending unit switch.
Oil pressure warning light bulb test occurs with ignition switch in
RUN position.
All instrument clusters include these analog gauges:
* Coolant Temperature Gauge
* Fuel Gauge
* Oil Pressure Gauge
* Speedometer
* Voltmeter
Instrument clusters include these indicator lights, if
vehicle is equipped with appropriate option:
* Air Bag
* Anti-Lock Brake System (ABS)
* Brake Warning
* Check Gauges
* Cruise On
* Headlight High Beam
* Low Fuel
* Low Washer Fluid
* CHECK ENGINE
* Overdrive Off
* Rear Wheel Anti-Lock (RWAL)
* Seat Belt Reminder
* Security
* Transmission Oil Temperature (A/T)
* Turn Signal
* Upshift (M/T)
* 4WD
SELF-DIAGNOSTIC SYSTEM
WARNING: Vehicle is equipped with an air bag system. To prevent air
bag deployment, disconnect negative battery cable and wait at
least 2 minutes before servicing instrument cluster. See
appropriate AIR BAG RESTRAINT SYSTEMS article.
CAUTION: When battery is disconnected, vehicle computer and memory

cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION.
Reconnect negative battery cable. Measure voltage between ground and
terminal No. 6 (Pink/White wire) of instrument cluster connector C1.
See Fig. 1 . If battery voltage is present, reinstall instrument
cluster and go to SELF- DIAGNOSTICS. If battery voltage is not
present, repair open circuit between fuse No. 12 (15-amp) in junction
block and instrument cluster connector C1 and go to next step.
5) Remove and inspect fuse No. 11 (10-amp) in junction block\
.
If fuse is okay, go to next step. If fuse is blown, locate and repair
cause of blown fuse. Install new fuse and recheck system operation.
6) Turn ignition on. Measure voltage between ground and power
side (Dark Blue/White wire) of fuse No. 11 (10-amp) in junction bloc\
k.
If battery voltage is present, go to step 8). If battery voltage is
not present, locate and repair open circuit to fuse No. 11. See WIRING
DIAGRAMS.
7) Turn ignition off and disconnect negative battery cable.
Install instrument cluster. Connect negative battery cable. Turn
ignition on. Set parking brake and observe instrument cluster brake
warning light. If brake warning light is on, go to next step. If brake
warning light is off, go to step 9).
8) Turn ignition off. Turn parking lights on and adjust
instrument panel lights dimmer rheostat to full bright position. If
instrument panel lights are on, go to step 10). If instrument panel
lights are off, repair instrument cluster illumination ground circuit
between instrument cluster connector C2 terminal No. 7 (Black wire)
and ground. See WIRING DIAGRAMS.
9) Turn ignition off and disconnect negative battery cable.
Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL &
INSTALLATION. Connect negative battery cable. Turn ignition on.
Measure voltage between ground and terminal No. 2 (Dark Blue/White
wire) at instrument cluster connector C1. If battery voltage is
present, go to SELF-DIAGNOSTICS. If battery voltage is not present,
repair open circuit between junction block fuse No. 11 and instrument
cluster.
10) Turn ignition off and disconnect negative battery cable.
Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL &
INSTALLATION. Check continuity between ground and terminal No. 4
(Black/Dark Green wire) at instrument cluster connector C1. If
continuity exists, go to SELF-DIAGNOSTICS. If continuity does not
exist, locate and repair open in ground circuit.
SELF-DIAGNOSTICS
1) With ignition off, press and hold trip odometer RESET
button while turning ignition switch to ON position. Continue to hold
RESET button until odometer window displays CHEC (about 10 seconds).
Release RESET button. If problem exists, system will display
Diagnostic Trouble Codes (DTC). See DIAGNOSTIC CODE CHART table. For
repairs of DTCs, see appropriate BODY CONTROL COMPUTER TESTS article.
DIAGNOSTIC TROUBLE (DTC) CODE CHART







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DTC Description  Correction 




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110 Cluster CPU, RAM Or EEPROM Fault  Replace Cluster 




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900 CCD Bus Inoperative Check CCD Bus Connections At

  Cluster; Check Cluster 

  Fuses; Check CCD Bus Bias;

  Check CCD Bus Voltage; 

  Check CCD Bus Terminations 




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920 Not Receiving VSS Message From PCM Check PCM Software Level; 

CAUTION: If fuel contamination due to fungi or other microorganisms is
suspected a fuel additive with a biocide may be used. Follow
the manufacturers dosage as recommended on product label. Use
biocides ONLY when necessary, excessive use can may cause
other fuel system problems.
DIESEL FUEL CONTAMINATION
WARNING: Diesel fuel system may be contaminated with fungi or other
microorganisms. Keep contaminated fuel away from open skin
cuts or sores to prevent skin irritation or infection.
DIESEL FUEL REQUIREMENTS
CAUTION: All diesel engines have been developed to take advantage of
the high energy content of No. 2 diesel fuel or No. 2
climatized-diesel fuels. It also operates on No. 1-diesel
fuels if temperatures are expected to be extended arctic
conditions -10
\bF (-23\bC).
WARNING: Do NOT use alcohol or gasoline as a fuel blending agent. They
can be unstable under certain conditions and hazardous or
explosive when mixed with diesel fuel.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
WARNING: Many solid state electrical components can be damaged by
static electricity (ESD). Some will display a warning label,
but many will not. Discharge personal static electricity by
touching a metal ground point on the vehicle prior to
servicing any ESD sensitive component.
ENGINE OIL
CAUTION: Never use non-detergent or straight mineral oil.
ENGINE OIL FILTER (CARTRIDGE TYPE)
CAUTION: Use of Mopar Oil Filter Cartridge (P/N 04746914) is
RECOMMENDED. The engine oil filter cartridge should be
changed at every engine oil change. Use the same type oil
that will be used in the engine.
FUEL SYSTEM SERVICE
WARNING: Relieve fuel system pressure prior to servicing any fuel
system component (fuel injection models).
HALOGEN BULBS
WARNING: Halogen bulbs contain pressurized gas which may explode if
overheated. DO NOT touch glass portion of bulb with bare
hands. Eye protection should be worn when handling or working
around halogen bulbs.
RADIATOR CAP
CAUTION: Always disconnect the fan motor when working near the
radiator fan. The fan is temperature controlled and could
start at any time even when the ignition key is in the OFF
position. DO NOT loosen or remove radiator cap when cooling
system is hot.

Crankcase Ventilation (PCV) system, but does not use a vacuum
controlled valve. See POSITIVE CRANKCASE VENTILATION (PCV).
EVAPORATIVE (EVAP) EMISSIONS SYSTEM
This system stores fuel vapors from fuel tank, preventing
vapors from reaching the atmosphere. As fuel evaporates inside fuel
tank, vapors are routed through vent hoses to charcoal canister where
they are stored until engine is started.
Evaporative Canister Purge Control Solenoid (EVAP-CPCS)
Charcoal canister purging is controlled by PCM through an
EVAP-CPCS. During engine warm-up and for a short period after hot
restarts, PCM energizes EVAP-CPCS, interrupting engine vacuum signal
to charcoal canister.
After engine reaches a predetermined operating temperature
and PCM internal timer has expired, PCM will de-energize EVAP-CPCS,
allowing engine vacuum to purge charcoal canister. EVAP-CPCS will also
be de-energized during certain idle conditions so PCM can update fuel
delivery calibration.
POSITIVE CRANKCASE VENTILATION (PCV)
PCV system uses a vacuum operated valve. A closed engine
crankcase breather/filter, with a hose connecting it to air filter
housing, provides source of air for system. Crankcase blow-by gases
are removed from crankcase through PCV valve with manifold vacuum.
These gases are introduced into incoming air/fuel mixture and become
part of the calibrated mixture.
A non-vacuum operated Crankcase Ventilation (CCV) system is
used on some engines, see CRANKCASE VENTILATION (CCV) SYSTEM.
SELF-DIAGNOSTIC SYSTEM
The PCM monitors several different circuits of engine control
system. If a problem is sensed with a monitored circuit, PCM will
store a Diagnostic Trouble Code (FTC) to aid technician in diagnosis
of system. The Malfunction Indicator Light (MIL), or a scan tool can
be used to read DTCs. For additional information, see SELF-DIAGNOSTICS
- JEEP, TRUCKS & RWD VANS article.
MALFUNCTION INDICATOR LIGHT
Malfunction Indicator Light (MIL) comes on and remains on for\
3 seconds as a bulb test each time ignition switch is turned to ON
position. If PCM receives an incorrect signal or receives no signal
from battery voltage input, charging system, ECT sensor, MAP sensor or
TP sensor, MIL will come on. MIL will also come on if certain
emission-related faults exist. This warns driver that PCM is in limp-
in mode and immediate repairs are necessary. See LIMP-IN MODE under
MISCELLANEOUS CONTROLS. MIL can also be used to display Diagnostic
Trouble Codes (DTCs). For additional information, see SELF-DIAGNOSTICS\
- JEEP, TRUCKS & RWD VANS article.
SERIAL COMMUNICATIONS INTERFACE (SCI)
SCI circuit is used by PCM to send data to and receive data
and sensor activation signals from scan tool. Scan tool uses signals
sent on SCI to display fault messages or Diagnostic Trouble Codes
(DTCs), sensor voltages and device states (On/Off). Scan tool uses S\
CI
to send solenoid and switch activation commands to PCM so that devices
and circuits can be tested. SCI is also used to write SRI mileage to

resistance between ground and instrument cluster connector C1 terminal
No. 10 (Violet/Brown wire). If resistance is less than 5 ohms, replace\
instrument cluster. If resistance is 5 ohms or more, repair open
Violet/Brown wire.
BUS (+) & BUS (-) SHORTED TOGETHER
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Turn ignition off. Disconnect Powertrain Control Module
(PCM). PCM is mounted in right side of firewall. Turn ignition on. If
scan tool does not display BUS (+) & BUS (-) SHORTED TOGETHER, repla\
ce
PCM. If scan tool displays BUS (+) & BUS (-) SHORTED TOGETHER, go to\
next step.
2) Turn ignition off. Disconnect anti-lock brake controller
module. Controller is mounted to top of ABS hydraulic unit. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace anti-lock brake controller module. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
3) Turn ignition off. Disconnect instrument cluster. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace instrument cluster circuit board. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
4) Turn ignition off. Disconnect compass mini-trip computer.
Turn ignition on. If scan tool does not display BUS (+) & BUS (-)
SHORTED TOGETHER, replace compass mini-trip computer. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
5) Turn ignition off. Disconnect radio connector. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace radio. If scan tool displays BUS (+) & BUS (-)
SHORTED TOGETHER, go to next step.
6) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool does not display BUS (+) & BUS (-)
SHORTED TOGETHER, replace ACM. If scan tool displays BUS (+) & BUS (-\
)
SHORTED TOGETHER, go to next step.
7) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is located under left side of instrument panel. Turn ignition on.
If scan tool does not display BUS (+) & BUS (-) SHORTED TOGETHER,
replace CTM. If scan tool displays BUS (+) & BUS (-) SHORTED TOGETHE\
R,
go to next step.
8) Disconnect scan tool from DLC. Using external ohmmeter,
measure resistance between terminals No. 3 (Violet/Brown wire) and No.\
11 (White/Black wire) on DLC connector. If resistance is less than 5
ohms, repair short between Violet/Brown wire and White/Dark Green
wire. If resistance is 5 ohms or more, replace scan tool cable or scan
tool as necessary.
BUS BIAS LEVEL TOO LOW (BUS BIAS LEVEL TOO HIGH)
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Disconnect scan tool. Using an external voltmeter, measure

CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Remove and inspect fuse No. 11 from junction block.
Junction block is on left side of instrument panel. If fuse is open,
go to next step. If fuse is okay, go to step 3).
2) Using external ohmmeter, measure resistance between ground
and fused ignition switch output run/start terminal (Dark Blue/White
wire) on fuse No. 11 socket. If resistance is less than 5 ohms, repair
short to ground in Dark Blue/White wire. Replace fuse No. 11. If
resistance is 5 ohms or more, replace fuse No. 11.
3) Install fuse No. 11. Remove and inspect fuse No. 6 from
junction block. If fuse is open, next step. If fuse is okay, go to
step 5).
4) Using external ohmmeter, measure resistance between ground
and fused ignition switch output run/accy terminal (Dark Blue wire) on\
fuse No. 6 socket. If resistance is less than 5 ohms, repair short to
ground in Dark Blue wire. Replace fuse No. 6. If resistance is 5 ohms
or more, replace fuse No. 6.
5) Install fuse No. 6. Disconnect Central Timer Module (CTM)\
.
CTM is located under left side of instrument panel. Using external
ohmmeter, measure resistance between ground and CTM 18-pin connector
terminal No. 3 (Black/Orange wire). If resistance is more than 5 ohms,\
repair open Black/Orange wire. If resistance is 5 ohms or less, go to
next step.
6) Measure resistance between ground and CTM 14-pin connector
terminal No. 6 (Black/Light Green wire). If resistance is more than 5
ohms, repair open Black/Light Green wire. If resistance is 5 ohms or
less, go to next step.
7) Turn ignition on. Using scan tool, perform CCD Bus test.
Connect jumper wire between ground and CTM 18-pin connector terminal
No. 16 (Violet/Brown wire). If scan tool does not display BUS SHORT TO\
GROUND, repair open Violet/Brown wire. If scan tool displays BUS SHORT
TO GROUND, go to next step.
8) Disconnect jumper wire. Connect jumper wire between ground
and CTM 18-pin connector terminal No. 17 (White/Black wire). If scan
tool does not display BUS SHORT TO GROUND, repair open White/Black
wire. If scan tool displays BUS SHORT TO GROUND, replace CTM.
NO RESPONSE INSTRUMENT CLUSTER
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 off prior to disconnecting any module
connector.
1) Turn ignition on. Using scan tool, select BODY CONTROL
MODULE. If scan tool displays NO RESPONSE, go to NO RESPONSE CENTRAL
TIMER MODULE. If scan tool does not display NO RESPONSE, go to next
step.
2) Using scan tool, select SYSTEM TEST. If scan tool displays
PCM ACTIVE ON THE BUS, go to next step. If scan tool does not display
PCM ACTIVE ON THE BUS, go to NO RESPONSE POWERTRAIN CONTROL MODULE.
3) Turn ignition off. Remove instrument cluster. Turn
ignition on. Using scan tool, turn on CCD bus bias under SYSTEM
MONITORS, then CCD BUS VOLTAGE. Connect jumper wire between ground and
instrument cluster connector C1 terminal No. 10 (Violet/Brown wire).
If scan tool voltage did not drop to about zero volts, repair open
Violet/Brown wire. If scan tool voltage dropped to about zero volts,
go to next step.

4) Move jumper to instrument cluster connector C1 terminal
No. 9 (White/Black wire). Monitor CCD BUS VOLTAGE. If scan tool
voltage did not drop to about zero volts, repair open White/Black
wire. If scan tool voltage did not drop to about zero volts, replace
instrument cluster.
NO RESPONSE POWERTRAIN CONTROL MODULE
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) If engine does not run, see appropriate BASIC DIAGNOSTIC
PROCEDURES article in ENGINE PERFORMANCE section. If engine runs, go
to next step.
2) Turn ignition off. Disconnect Powertrain Control Module
(PCM). PCM is mounted in right side of firewall. Turn ignition on.
Connect jumper wire between ground and PCM connector C3 terminal. No.
30 (Violet/Brown wire). Using scan tool, perform CCD BUS test. If scan\
tool does not display SHORT TO GROUND, repair open Violet/Brown wire.
If scan tool displays SHORT TO GROUND, go to next step.
3) Move jumper wire to PCM connector C3 terminal No. 28
(White/Black wire). Perform CCD BUS test. If scan tool does not
display SHORT TO GROUND, repair open White/Black wire. If scan tool
displays SHORT TO GROUND, replace PCM.
NO RESPONSE COMPASS/MINI-TRIP SYSTEM
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Remove and inspect fuse No. 11 from junction block.
Junction block is on left side of instrument panel. If fuse is open,
go to next step. If fuse is okay, go to step 3).
2) Using external ohmmeter, measure resistance between ground
and fused ignition switch output run/start terminal (Dark Blue/White
wire) on fuse No. 11 socket. If resistance is less than 5 ohms, repair
Dark Blue/White wire for short to ground. Replace fuse No. 11. If
resistance is 5 ohms or more, replace fuse No. 11.
3) Reinstall fuse. Disconnect CMTC 12-pin connector. Turn
ignition on. Using external voltmeter, measure voltage between ground
and CMTC connector terminal No. 1 (Dark Blue/White wire). If voltage
is less than 9.5 volts, repair open Dark Blue/White wire. If voltage
is 9.5 volts or more, go to next step.
4) Using external voltmeter, measure voltage between ground
and CMTC connector terminal No. 5 (Pink wire). If voltage is less than\
9.5 volts, repair open Pink wire. If voltage is 9.5 volts or more, go
to next step.
5) Turn ignition off. Using external ohmmeter, measure
resistance between ground and CMTC connector terminal No. 7
(Black/Light Green wire). If resistance is 5 ohms or less, go to next
step. If resistance is more than 5 ohms, repair open Black/Light Green
wire.
6) Using scan tool, perform CCD bus test. Connect jumper wire
between ground and CMTC connector terminal No. 2 (Violet/Brown wire).
If scan tool displays BUS (+) SHORTED TO GROUND, go to next step. If

scan tool does not display BUS (+) SHORTED TO GROUND, repair open
Violet/Brown wire.
7) Move jumper wire to CMTC connector terminal No. 8
(White/Black wire). If scan tool displays BUS (+) SHORTED TO GROUND,\
replace CMTC. If scan tool does not display BUS (+) SHORTED TO GROUND,\
repair open White/Black wire.
NO RESPONSE RADIO
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 off prior to disconnecting any module
connector.
1) If radio screen is not blank, go to step 7). If radio
screen is blank, go to next step.
2) Remove and inspect junction block fuse No. 8 (radio). If
fuse is blown, go to next step. If fuse is okay, go to step 4).
3) Turn ignition off. Disconnect radio Gray connector. Using
external ohmmeter, measure resistance between ground and radio Gray
connector terminal No. 6 (Red/White wire). If resistance is less than
5 ohms, repair Red/White wire for short to ground. Replace junction
block fuse No. 8. If resistance is 5 ohms or more, replace radio.
Replace junction block fuse No. 8.
4) Turn ignition on. Measure voltage between ground and
terminal No. 7 (Pink wire). If voltage is 10 volts or less, repair
open Pink wire. If voltage is more than 10 volts, go to next step.
5) Install fuse. Disconnect radio Gray connector. Using
external voltmeter, measure voltage between ground and radio Gray
terminal No. 6 (Red/White wire). If voltage is 10 volts or less,
repair open Red/White wire. If voltage is more than 10 volts, go to
next step.
6) Inspect ground strap and antenna for correct installation.
Repair as needed. If ground strap and antenna are okay, replace radio.
7) Disconnect 2-pin CCD BUS connector on back of radio.
Connect jumper wire between terminal No. 2 (White/Black wire) and
ground. Using scan tool, select BODY, BODY COMPUTER, then SYSTEM TEST.
Perform CCD BUS test. If scan tool does not display BUS SHORT TO
GROUND, repair open White/Black wire. If scan tool displays BUS SHORT
TO GROUND, go to next step.
8) Move jumper wire to terminal No. 1 (Violet/Brown wire).
Perform CCD BUS test. If scan tool does not display BUS SHORT TO
GROUND, repair open Violet/Brown wire. If scan tool displays BUS SHORT
TO GROUND, replace radio.
NO TERMINATION
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Disconnect Powertrain Control Module (PCM) connectors. PC\
M
is mounted in right side of firewall. Connect jumper wire between
ground and PCM connector C3 terminal No. 30 (Violet/Brown wire). Using\
scan tool, select SYSTEM MONITORS. Perform CCD BUS test. If scan tool
does not display BUS SHORT TO GROUND, repair open Violet/Brown wire.
If scan tool displays BUS SHORT TO GROUND, go to next step.
2) Move jumper wire to PCM connector C3 terminal No. 28

(White/Black wire). Perform CCD BUS test. If scan tool does not
display BUS SHORT TO GROUND, repair open White/Black wire. If scan
tool displays BUS SHORT TO GROUND, replace PCM.
NOT RECEIVING BUS MESSAGES CORRECTLY
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Disconnect anti-lock brake controller module. Controller
module is mounted to top of ABS hydraulic unit. Turn ignition on. If
scan tool displays BUS OPERATIONAL, replace anti-lock brake controller
module. If scan tool does not display BUS OPERATIONAL, go to next
step.
2) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool displays BUS OPERATIONAL, replace ACM.
If scan tool does not display BUS OPERATIONAL, go to next step.
3) Disconnect Central Timer Module (CTM). CTM is located
under left side of instrument panel. Turn ignition on. If scan tool
displays BUS OPERATIONAL, replace CTM. If scan tool does not display
BUS OPERATIONAL, replace scan tool cable or scan tool.
BUS SHORT TO 5 VOLTS
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Turn ignition off. Disconnect Powertrain Control Module
(PCM). PCM is mounted in right side of firewall. Turn ignition on. If
scan tool does not display BUS SHORT TO 5 VOLTS, go to step 10). If
scan tool displays BUS SHORT TO 5 VOLTS, go to next step.
2) Turn ignition off. Disconnect anti-lock brake controller
module. Controller module is mounted to top of ABS hydraulic unit.
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace anti-lock brake controller module. If scan tool displays BUS
SHORT TO 5 VOLTS, go to next step.
3) Turn ignition off. Disconnect instrument cluster. Turn
ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace instrument cluster circuit board. If scan tool displays BUS
SHORT TO 5 VOLTS, go to next step.
4) Turn ignition off. Disconnect compass mini-trip computer.
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace compass mini-trip computer. If scan tool displays BUS SHORT TO
5 VOLTS, go to next step.
5) Turn ignition off. Disconnect CCD radio. Turn ignition on.
If scan tool does not display BUS SHORT TO 5 VOLTS, replace radio. If
scan tool displays BUS SHORT TO 5 VOLTS, go to next step.
6) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace ACM. If scan tool displays BUS SHORT TO 5 VOLTS, go to next
step.
7) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is mounted behind right corner of dash, beside glove box. Turn