
TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Engine Control Module harness connectors.
Check all of the engine control module's power circuits for a short or open condition.
Check all of the engine control module's ground circuits for an open condition.
Were any problems found?All
Ye s!Repair the power/ground circuit(s) as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the Engine Control Module harness connectors.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Engine Control Module harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Engine Control Module in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Automatic Temperature Control (ATC) C1 harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Automatic Temperature Control in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
164
HEATING & A/C
NO COMMUNICATION WITH ECM (ACTIVE) ÐContinued

Symptom:
WATER CYCLE VALVE CONTROL HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
WATER CYCLE VALVE
WATER CYCLE VALVE CONTROL CIRCUIT SHORTED TO VOLTAGE
AUTOMATIC TEMPERATURE CONTROL (ATC)
WATER CYCLE VALVE CONTROL CIRCUIT OPEN
GROUND CIRCUIT OPEN
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Press the Residual Engine Heat Utilization (REST) switch off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Water Cycle Valve harness connector.
Connect a 12-volt test light between the Water Cycle Valve Control circuit and the
Ground circuit in the Water Cycle Valve harness connector. The test light should
operate as follows:
With the Residual Engine Heat Utilization (REST) switch off, the test light should
not illuminate.
Press the Residual Engine Heat Utilization (REST) switch on.
With the Blend control set to Full Cold, the test light should illuminate brightly and
continuously.
With the Blend control set to one position below the half Cold/Hot setting, the test
light should illuminate brightly and blink at a slow continuous rate.
With the Blend control set to the half Cold/Hot setting or above, the test light should
be off.
Does the test light operate as specified?All
Ye s!Replace the Water Cycle Valve in accordance with the Service
Information.
Perform BODY VERIFICATION TEST - VER 1.
No, Light Illuminates With REST Off.
Go To 2
No, Light Will Not Illuminate
Go To 3
No, Light Won't Correspond To Blend
Go To 3
175
HEATING & A/C

TEST ACTION APPLICABILITY
4 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Reconnect the Automatic Temperature Control (ATC) C1 harness connector.
Press the Residual Engine Heat Utilization (REST) switch off.
Disconnect the Water Cycle Valve harness connector.
Connect a 12-volt test light between the Water Cycle Valve Control circuit and the
Ground circuit in the Water Cycle Valve harness connector. The test light should
operate as follows:
With the Residual Engine Heat Utilization (REST) switch off, the test light should
not illuminate.
Press the Residual Engine Heat Utilization (REST) switch on.
With the Blend control set to Full Cold, the test light should illuminate brightly and
continuously.
With the Blend control set to one position below the half Cold/Hot setting, the test
light should illuminate brightly and blink at a slow continuous rate.
With the Blend control set to the half Cold/Hot setting or above, the test light should
be off.
Does the test light operate as specified?All
Ye s!Replace the Water Cycle Valve in accordance with the Service
Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
178
HEATING & A/C
WATER CYCLE VALVE CONTROL SHORTED LOW (ACTIVE) ÐContinued

NAG1 TRANSMISSION VERIFICATION TEST - VER 1 APPLICABILITY
1. Reconnect any disconnected components.
2. Connect the DRBIIItto the Data Link Connector.
3. With the DRBIIIt, erase ABS DTCs.
4. With the DRBIIIt, erase ECM DTCs.
5. With the DRBIIIt, erase Transmission DTCs.
6. With the DRBIIIt, display Transmission Temperature. Start and run the engine until the
Transmission Temperature is HOT, above 43É C (110É F).
7. Check the Transmission fluid and adjust if necessary. Refer to the Service Information for the
proper Fluid Fill procedure.
8. NOTE: If internal repairs were performed and the shift quality is still poor, it may
be necessary to check the internal repair. Also check for any TSBs and/or Controller
Flash updates that may apply.
9. ROAD TEST PROCEDURE
10. Road test the vehicle. Make fifteen to twenty 1-2, 2-3, 3-4 and 4-5 upshifts.
11. Perform these shifts from a standing start to 72 km/h (45 MPH) with a constant throttle
opening of 20 to 25 degrees.
12. With speeds below 40 km/h (25 MPH), make five to eight wide open throttle kickdowns to
1st gear. Allow at least 5 seconds each in 2nd and 3rd gear between each kickdown.
13. With the DRBIIIt, read Transmission DTCs.
Were there any Diagnostic Trouble Codes set?All
Ye s!Repair is not complete, refer to appropriate symptom.
No!Repair is complete.
ROAD TEST VERIFICATION - VER-2 APPLICABILITY
1. Inspect the vehicle to ensure that all engine components are properly installed and
connected. Reassemble and reconnect components as necessary.
2. If this verification procedure is being performed after a non-DTC test, perform steps 3 and
4.
3. Check to see if the initial symptom still exists. If there are no trouble codes and the symptom
no longer exists, the repair was successful and testing is now complete.
4. If the initial or another symptom exists, the repair is not complete. Check all pertinent
Technical Service Bulletins (TSBs) and return to the Symptom List if necessary.
5. For previously read DTCs that have not been dealt with, return to the Symptom List and
follow the diagnostic path for that DTC; otherwise, continue.
6. If the Engine Control Module (ECM) has not been changed, perform steps 7 and 8, otherwise,
continue with step 9.
7. With the DRB IIIt, erase all diagnostic trouble codes (DTCs), then disconnect the DRB IIIt.
8. Turn the ignition off for at least 10 seconds.
9. If equipped with a Transfer Case Position Switch, perform step 10, otherwise, continue with
step 11.
10. With the ignition switch on, place the Transfer Case Shift Lever in each gear position,
stopping for 15 seconds in each position.
11. Ensure no DTCs remain by performing steps 12 through 15.
12. Road test the vehicle. For some of the road test, go at least 64 km/h (40 MPH). If this test
is for an A/C Relay Control Circuit, drive the vehicle for at least 5 minutes with the A/C on.
13. At some point, stop the vehicle and turn the engine off for at least 10 seconds, then restart
the engine and continue.
14. Upon completion of the road test, turn the engine off and check for DTCs with the DRB IIIt.
15. If the repaired DTC has set again, the repair is not complete. Check for any pertinent
Technical Service Bulletins (TSBs) and return to the Symptom List. If there are no DTCs, the
repair was successful and is now complete.
Are any DTCs or symptoms remaining?All
Ye s!Repair is not complete, refer to appropriate symptom.
No!Repair is complete.
247
VERIFICATION TESTS
Verification Tests ÐContinued

²Four Wheel Speed Sensors/Tone Wheel assem-
blies
²ABS warning indicator
²TCS (ASR) event indicator
²TCS (ASR) warning indicator
²Steering Angle Sensor
²Lateral Acceleration/Yaw Rate Sensor
²Brake Pressure Sensor
²ESP event indicator
²Brake Fluid Level switch
²Brake Switch (BS)
²Brake Lamp Switch (BLS)
²TCS Switch (TCSS)
²K - ABS
²CAN C Bus
²Fuses, grounds, and wiring
3.7.1 ABS AND TCS (ASR) INDICATORS
This system is equipped with an ABS warning
indicator, TCS (ASR) warning indicator, and TCS
(ASR) event indicator to alert the driver of a
malfunction/event it has detected. The CAB can
request the illumination of the ABS warning indi-
cator, TCS (ASR) warning indicator, and TCS (ASR)
event indicator via CAN C BUS. The CAB controls
the ABS warning indicator by:
²Light steady during an initial test at the begin-
ning of an ignition cycle to function as a bulb
check
²Light steady when a system malfunction exists
(DTC)
²Light steady - If you have not met the speed
required to reset/retest the ABS components
The Instrument Cluster (IC) controls the indica-
tors. The Instrument Cluster transmits a message
over the CAN C Bus relating to diagnostics and
current lamp status for the ABS and TCS (ASR)
indicators. The CAB can control the operation of
TCS warning and TCS event indicators by:
²Both light steady with engine off and both go out
with engine running
²TCS warning indicator lights steady when a TCS
malfunction exists
²TCS event indicator will flash when TCS is in an
active event
3.7.2 CONTROLLER ANTILOCK BRAKE
(CAB)
The CAB is mounted directly to the Hydraulic
Control Unit (HCU) that includes a microprocessor
and twelve solenoids that control valves that con-trol brake pressure during antilock braking or trac-
tion control events. The CAB also has circuits that
monitor the following:
²Double brake switch outputs are monitored to
determine whether or not to prepare for possible
ABS braking
²Wheel Speed Sensors are monitored to determine
when a wheel is tending to lock up. The CAB will
operate the valves in the HCU to control braking
pressure during ABS braking
²Detect ABS system related problems and take
diagnostic action
²Able to execute self-tests and output control com-
mands
When equipped with Electronic Stability (ESP),
the CAB also monitors the following:
²The ESP looks at the Steering Angle Sensor value
and monitors the speed of the inner and outer
wheels to ensure that the values are plausible.
The Steering Angle Sensor also monitors the
speed that the steering wheel is turned.
²The Lateral Acceleration/Yaw Rate Sensor is con-
tained in one unit. The sensor measures side to
side (lateral) motion and rotational motion (how
fast the vehicle is turning).
²The ESP uses data from the Brake Pressure
Sensor to analyze how hard and fast that the
driver wants to brake.
3.7.3 HYDRAULIC CONTROL UNIT (HCU)
The HCU on the Bosch 5.7 has an integral valve
body for controlling the front and rear brakes.
Within the HCU are inlet, outlet, and shuttle
valves, to release brake pressure as required to
avoid wheel lockup, keeping the wheels rolling, and
maintain optimum deceleration with stability. The
Pump Motor is attached to the HCU which works
with the ABS and TCS and is controlled by the
CAB. The primary function is to provide extra
amount of fluid when needed.
3.7.4 SWITCHES/SENSORS
BRAKE SWITCH (BS):This switch prepares the
CAB for a possible antilock event. The CAB uses an
output state voltage from the BS when the brake
pedal is either released/depressed. The Fused Igni-
tion Switch Output circuit supplies 12 volts to the
BS. A released brake pedal will close the BS circuit
and the BS Output circuit supplies 12 volts to the
CAB. When the driver depresses the brake pedal,
the BS Output circuit voltage drops to 0 volts and
the CAB senses the brake pedal state. This tells the
CAB what position the brake pedal is currently in to
make an ABS event possible. When using the
DRBIIItin Inputs/Outputs, the BS and BLS will
3
GENERAL INFORMATION

ver: 2.14
date: 26 Jul93
file: key_iff.cc
date: Jul 26 1993
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.9.1 DRBIIITDOES NOT POWER UP
(BLANK SCREEN)
If the LED's do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
16-way connector cavity 16). A minimum of 11 volts
is required to adequately power the DRBIIIt. Also
check for a good ground at DLC.
If all connections are proper between the
DRBIIItand the vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result or a faulty cable or
vehicle wiring.
3.9.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
4.0 DISCLAIMERS, SAFETY,
WARNINGS
4.1 DISCLAIMERS
All information, illustrations, and specifications
contained in this manual are based on the latestinformation available at the time of publication.
The right is reserved to make changes at any time
without notice.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially
important to block the wheels on front-wheel drive
vehicles; the parking brake does not hold the front
drive wheels.
When servicing a vehicle, always wear eye pro-
tection, and remove any metal jewelry such as
watchbands or bracelets that might make an inad-
vertent electrical contact.
When diagnosing an antilock brake or adjustable
pedals system problem, it is important to follow
approved procedures where applicable. These pro-
cedures can be found in the service manual. Follow-
ing these procedures is very important to safety of
individuals performing diagnostic tests.
4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB-ASSEMBLIES
Some components of the antilock brake and trac-
tion control are intended to be serviced in assembly
only. Attempting to remove or repair certain sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.
5
GENERAL INFORMATION

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the CAB harness connector.
Turn the ignition on.
Measure the voltage of the CAN(+) circuit.
Measure the voltage of the CAN(-) circuit.
Is the voltage above 3.0 volts for either circuit?All
Ye s!Repair the CAN circuit(s) for a short to voltage.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the CAB harness connector.
Measure the resistance between ground and the CAN(+) circuit.
Measure the resistance between ground and the CAN(-) circuit.
Is the resistance below 5.0 ohms for either circuit?All
Ye s!Repair the CAN circuit(s) for a short to ground.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 6
6 Turn the ignition off.
Disconnect the CAB harness connector.
Measure the resistance between the CAN(+) circuit and the CAN(-) circuit.
Is the resistance below 5.0 ohms between the circuits?All
Ye s!Repair the shorted CAN circuit(s).
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 7
7 Turn the ignition off.
Disconnect the Engine Control Module harness connector.
Disconnect the CAB harness connector.
Measure the resistance of the CAN(+) circuit.
Measure the resistance of the CAN(-) circuit.
Is the resistance above 5.0 ohms for either circuit?All
Ye s!Repair the CAN circuit(s) for an open
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 8
8 Turn the ignition off.
Disconnect the CAB harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Optional Equipment
Relay Output circuit at the CAB harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s!Go To 9
No!Repair the Fused Optional Equipment Relay Output circuit for an
open.
Perform ABS VERIFICATION TEST - VER 1.
26
BRAKES (CAB)
CAN COMMUNICATION ERROR ÐContinued

TEST ACTION APPLICABILITY
1NOTE: If a system undervoltage or overvoltage DTC is set along with this
DTC, diagnose the system voltage DTC first.
Turn the ignition on.
With the DRBIIIt, read DTCs.
With the DRBIIIt, erase DTCs.
Turn the ignition off.
Turn the ignition on.
Start the engine.
Drive the vehicle over 15 km/h (10 mph) to test solenoid and pump circuits.
Stop the vehicle.
With the DRBIIIt, read DTCs.
Does the DRBIIItdisplay any SOLENOID DTCs?All
Ye s!Go To 2
No!Go To 6
2 Turn the ignition off.
Disconnect the CAB harness connector.
Inspect the CAB/CAB harness connector for damage.
Is there any broken, bent, pushed out, corroded or spread terminals?All
Ye s!Repair as necessary.
Perform ABS VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
Disconnect the CAB harness connector.
Turn the ignition on.
Using a 12-volt test light connected to ground, check the Fused Optional Equipment
Relay Output circuit at the CAB harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s!Go To 4
No!Repair the Fused Optional Equipment Relay Output circuit for an
open.
Perform ABS VERIFICATION TEST - VER 1.
4 Turn the ignition off.
Disconnect the CAB harness connector.
Using a 12-volt test light connected to ground, check both Fused B(+) circuits at the
CAB harness connector.
NOTE: The test light must illuminate brightly. Compare the brightness to
that of a direct connection to the battery.
Does the test light illuminate brightly?All
Ye s!Go To 5
No!Repair the Fused B(+) circuit for an open.
Perform ABS VERIFICATION TEST - VER 1.
41
BRAKES (CAB)
LEFT FRONT INLET SOLENOID ÐContinued