JEEP CHEROKEE 1988 Service Repair Manual
Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
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volts, check charging system.
KEYPAD TEST FAILURE
1) If KEYPAD TEST FAILURE message is displayed, disconnect
DRB-II from transmission diagnostic connector. DO NOT touch keys on
DRB-II keypad. Reconnect DRB-II to transmission diagnostic connector
and note display.
2) If KEYPAD TEST FAILURE message is not displayed, proceed
with diagnostics. If KEYPAD TEST FAILURE message is displayed, replace
DRB-II and proceed with diagnostics.
LOW BATTERY
If LOW BATTERY message is displayed, use external voltmeter
to check battery voltage at battery terminals. If battery voltage is
11.7-13.0 volts, replace DRB-II. If battery voltage is not 11.7-13.0
volts, check charging system.
RAM TEST FAILURE
1) If RAM TEST FAILURE message is displayed, disconnect DRB-
II from transmission diagnostic connector. DO NOT touch keys on DRB-II
keypad. Reconnect DRB-II to transmission diagnostic connector and note
display.
2) If RAM TEST FAILURE message is not displayed, proceed with
diagnostics. If RAM TEST FAILURE message is displayed, replace DRB-II
and proceed with diagnostics. If KEYPAD TEST FAILURE message is
displayed, replace DRB-II and proceed with diagnostics.
COMPONENT TESTING
BRAKE SWITCH
Brake switch is mounted above brake pedal. When brake pedal
is operated, brake switch delivers an input signal to TCM. The TCM
uses input signal for controlling No. 3 valve body solenoid for torque
converter lock-up. No other information is available from
manufacturer.
NOTE: For proper brake switch adjustment, see BRAKE SWITCH under
REMOVAL & INSTALLATION .
NEUTRAL SAFETY SWITCH
NOTE: Neutral safety switch may be referred to as park/neutral or
gear select switch. For proper neutral safety switch
adjustment, see NEUTRAL SAFETY SWITCH under REMOVAL &
INSTALLATION.
Disconnect electrical connector. Note terminal
identification. See Fig. 4. Using ohmmeter, check continuity between
specified terminals in relation to shift lever position. See NEUTRAL
SAFETY SWITCH CONTINUITY SPECIFICATIONS table. Replace neutral safety
switch if continuity is not as specified.
NEUTRAL SAFETY SWITCH CONTINUITY SPECIFICATIONS
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Shift Lever Continuity
Position Between Terminals
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Park ........................................... "B" & "C"
Reverse ........................................ "A" & "E"
Neutral ........................................ "B" & "C"
Drive ................................................ (1)
3 .............................................. "A" & "G"
1-2 ............................................ "A" & "H"
( 1) - No continuity should exist between any terminals.
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Fig. 4: Identifying Neutral Safety Switch Terminals
Courtesy of Chrysler Corp.
SPEED SENSOR
1) Disconnect electrical connector at speed sensor located on
adapter housing or extension housing. Connect ohmmeter leads between
speed sensor electrical terminals.
2) Rotate transmission output shaft and note ohmmeter
reading. Ohmmeter needle should fluctuate to indicate speed sensor
operation. Replace speed sensor if no reading is obtained.
THROTTLE POSITION SENSOR (TPS)
NOTE: Digital voltmeter must be used to check TPS.
1) Note location of TPS electrical connector. See Fig. 5.
Turn ignition on. Using digital voltmeter, check output voltage at
center terminal with throttle plate closed (idle position) and wide
open (full throttle).
2) With throttle plate closed (idle position), output voltag\
e
should be greater than 200 millivolts. With throttle plate wide open
(full throttle), output voltage should be less than 4.8 volts.
3) Ensure output voltage gradually increases as throttle
plate is moved from closed to wide open throttle. If no voltage
exists, check for defective wiring circuits or connections. Replace
TPS if defective.
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Fig. 5: Identifying TPS Electrical Connector
Courtesy of Chrysler Corp.
VALVE BODY SOLENOID
With oil pan removed, disconnect electrical connector from
valve body solenoid. Using ohmmeter, check resistance between valve
body solenoid electrical terminal and solenoid mounting bracket.
Replace valve body solenoid if resistance is not 11-15 ohms.
TROUBLE SHOOTING CHARTS & CODE CHARTS
NOTE: Following trouble shooting charts and illustrations are
courtesy of Chrysler Corp. Always start by performing
TEST 1A - VERIFICATION OF THE COMPLAINT . When diagnosing
transmission, it may be necessary to verify TCM connector
terminals, circuits and function, See Fig. 6.
NOTE: When using trouble shooting charts, Transmission Control
Module (TCM) may be referred to as Transmission Control Unit
(TCU). Diagnostic trouble code may be referred to as fault
code. Neutral safety switch may be referred to as
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park/neutral or gear select switch.
Fig. 6: TCM Connector Terminals I.D., Circuits & Functions
Courtesy of Chrysler Corp.
TEST 1A - VERIFICATION OF THE COMPLAINT
NOTE: ALWAYS start diagnosis with the most recent code.
1) Begin your testing of the transmission with a thorough
visual inspection.
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2) Connect the DRB-II to the transmission diagnostic
connector. See RETRIEVING FAULT CODES under SELF-DIAGNOSTIC SYSTEM for
diagnostic connector location.
CAUTION: If the vehicle is in 3rd or OD position and feels like it
is stuck in 3rd or jumping from 2-1 or 3-1, perform
TEST 10A - TESTING FOR INTERMITTENT SPEED SENSOR test below.
3) With the DRB-II, perform SYSTEM TEST. See SYSTEM TEST MODE
under DRB-II OPERATING MODES .
4) The DRB-II will instruct you to do some actions during the
System Test. The DRB-II will then look for the action to happen and
automatically go to the next test function. If you perform the
required action and the DRB-II does not move to the next function,
press ENTER. The DRB-II will continue the testing.
5) When the DRB-II states "VEHICLE DRIVE", the vehicle be
must be driven at a speed above 4 miles per hour to ensure accurate
testing of the vehicle speed sensor. Afterwards, the DRB-II will
display any fault codes that may be present.
6) When the system test is complete, if there are any fault
codes present, the DRB-II will automatically display the code(s).
7) There are two types of faults for the transmission
solenoids. They are displayed as "FAULT STORED" and "FAULT PRESENT".
Note that the tests are different in the chart below.
8) Perform the tests shown below in response to the indicated
fault codes.
NOTE: ALWAYS start diagnosis with the most recent code.
CODE-TO-TEST MENU
CODE-TO-TEST MENU \
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Code: Solenoid Affected: Fault Status: Perform:
\b \
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\b \
\b \
None None Affected No Faults Test 2A
\b \
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\b \
\b \
700 Solenoid No. 1 Fault Present Test 4A
\b \
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\b \
700 Solenoid No. 1 Fault Stored Test 3A
\b \
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\b \
700 Solenoid No. 2 Fault Present Test 4B
\b \
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\b \
700 Solenoid No. 2 Fault Stored Test 3A
\b \
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\b \
\b \
700 Solenoid No. 3 Fault Present Test 4C
\b \
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\b \
\b \
700 Solenoid No. 3 Fault Stored Test 3A
\b \
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\b \
\b \
702 Speed Sensor Fault Test 5A
\b \
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\b \
\b \
703 Gear Select Fault Test 6A
\b \
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\b \
\b \
705 TPS Fault Test 7A
\b \
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\b \
\b \
708 Wrong TCU Test 9A
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\f
TEST 2A - VERIFICATION TEST
NOTE: Perform TEST 1A - VERIFICATION OF THE COMPLAINT
before proceeding.
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This test verifies the correct operation of the AW4
transmission. It must be performed after finding no faults using the
DRB-II, and after a vehicle repair has been made.
1) Turn ignition key to "OFF".
2) Hold the MODE key and press the ATM key on the DRB-II at
the same time to restart the DRB-II.
3) Turn ignition key to "ON".
4) Reconnect all previously disconnected connectors.
5) Verify that the AW4 transmission control unit is properly
mounted.
6) Make sure the transmission fluid is at the proper level.
Check the fluid with the transmission temperature hot, the vehicle on
level ground, and the gear selector in neutral.
7) If any repairs have been made, test the vehicle as
instructed in TEST 1A - VERIFICATION OF THE COMPLAINT , and read faults
using the DRB-II. If there are any fault messages present, repeat TEST
1A - VERIFICATION OF THE COMPLAINT.
TEST 3A - STORED DIAGNOSTIC TROUBLE CODES TEST
NOTE: Perform TEST 1A - VERIFICATION OF THE COMPLAINT
before proceeding.
1) At this point, the Visual Inspection has been performed, a
"FAULT STORED" code has been found and the vehicle has been test
driven. The fault code is not "FAULT PRESENT", so it cannot be
considered a CURRENT or HARD fault.
2) All solenoid circuits are in the same harness and a common
ground wire is used for the solenoids. Use the following figures to
identify the harness and connector to inspect. See Fig. 7 and 8. if
all 3 solenoid faults are present, repair the Black wire (Cherokee)
ground wire open condition.
3) Carefully inspect the entire suspected circuit. Pay
particular attention to connectors, corrosion, accident damage, and
improper or missing parts.
4) If any problems are found, make the appropriate repair.
Then perform TEST 1A using the DRB-II.
5) Erase fault codes.
6) If no problems are found, perform the SYSTEM TEST using
the DRB-II. Re-check for fault codes. If there are no fault codes,
perform TEST 2A - VERIFICATION TEST . If fault code(s) return, perform
TEST 1A - VERIFICATION OF THE COMPLAINT .
Fig. 7: Test 3A - Location of 7-Way Connector
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Fig. 8: Test 3A - View of 7-Way Connector (Cherokee)
TEST 4A - CODE 700 - S1 SOLENOID CIRCUIT
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Fig. 9: Test 4A - Code 700, Flow Chart (1 of 2)
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Fig. 10: Test 4A - Code 700, Schematic (Cherokee)
Fig. 11: Test 4A - Code 700, TCU 32-Way Connector (Cavity 16)
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Fig. 12: Test 4A - Code 700, Location of 7-Way Connector
Fig. 13: Test 4A - Code 700, Location of Pin "B" (Ground)