Page 2200 of 2305

Symptom:
ABS CAN MESSAGE INCORRECT
When Monitored and Set Condition:
ABS CAN MESSAGE INCORRECT
When Monitored: ABS CAN messages received at least once and CAN Bus Circuit (37) is
not active
Set Condition: DTC Detected if the number of bytes incorrect for CAN ID.
POSSIBLE CAUSES
ABS - INTERNAL
TCM - INTERNAL
TEST ACTION APPLICABILITY
1NOTE: Low fluid level can be the cause of many transmission problems. If
the fluid level is low locate and repair the leak then check and adjust the
fluid level per the service information.
NOTE: Always perform diagnostics with a fully charged battery to avoid
false symptoms.
With the DRBIIIt, read the engine DTCs. Check and repair all engine DTCs prior to
performing transmission symptom diagnostics.
With the DRBIIIt, read and record all Transmission DTCs.
NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal
connections can set DTCs.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all
diagnostic monitors have run.
Note: Verify flash level of transmission controller. Some problems are
corrected by software upgrades to the transmission controller.
NOTE: Check for any Technical Service Bulletins that may apply.
Perform this procedure prior to Symptom diagnosis.All
Continue
Go To 2
2 Turn the ignition off to the lock position.
Replace the ABS Control Module per the Service Information.
Ignition on, engine not running.
With the DRBIIIt, erase Transmission DTCs.
Start the engine and with the brakes firmly applied place the gear selector into Drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ABS CAN MESSAGES INCORRECT, reset?All
Ye s!Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test complete.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
35
TRANSMISSION - NAG1
Page 2202 of 2305

TEST ACTION APPLICABILITY
2 Ignition on, engine not running.
With the DRBIIIt, read Transmission DTCs.
NOTE: If the DTC, CAN BUS CIRCUIT, is present, perform diagnostics on
that symptom first.
Is the DTC, CAN BUS CIRCUIT, present?All
Ye s!Refer to the Transmission category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 3
3 Ignition on, engine not running.
With the DRBIIIt, read ABS DTCs.
Are there any performance or bus related ABS DTCs present?All
Ye s!Repair all ABS DTCs before proceeding.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the ABS harness connector.
Disconnect the TCM C2 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance of the CAN Bus + circuit between the ABS harness connector
and the TCM C2 harness connector.
Measure the resistance of the CAN Bus - circuit between the ABS harness connector
and the TCM C2 harness connector.
Is the resistance above 5.0 ohms on either circuit?All
Ye s!Repair the CAN BUS + or - circuit for an open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 5
5 Replace and program the ABS Control Module.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ABS CAN MESSAGE MISSING, reset?All
Ye s!Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test complete.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
37
TRANSMISSION - NAG1
ABS CAN MESSAGE MISSING ÐContinued
Page 2222 of 2305
TEST ACTION APPLICABILITY
3 Replace and program the ECM per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ENGINE CAN MESSAGE INCORRECT, reset?All
Ye s!Go To 4
No!Test Complete
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
4 If there are no possible causes remaining, view repair. All
Repair
Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
57
TRANSMISSION - NAG1
ENGINE CAN MESSAGE INCORRECT ÐContinued
Page 2224 of 2305

TEST ACTION APPLICABILITY
2 Ignition on, engine not running.
With the DRBIIIt, read Transmission DTCs.
NOTE: If the DTC, CAN BUS CIRCUIT, is present, perform diagnostics on
that symptom first.
Is the DTC, CAN BUS CIRCUIT, present?All
Ye s!Refer to the Transmission category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 3
3 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any performance or bus related Engine DTCs present?All
Ye s!Refer to the Powertrain category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the ECM harness connector(s).
Disconnect the TCM C2 harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance of the CAN Bus + circuit between the ECM harness connector
and the TCM C2 harness connector.
Measure the resistance of the CAN Bus - circuit between the ECM harness connector
and the TCM C2 harness connector.
Is the resistance above 5.0 ohms on either circuit?All
Ye s!Repair the CAN BUS + or - circuit for an open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 5
5 Replace and program the ECM per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ENGINE CAN MESSAGE MISSING, reset?All
Ye s!Go To 6
No!Test Complete
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
6 If there are no possible causes remaining, view repair. All
Repair
Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
59
TRANSMISSION - NAG1
ENGINE CAN MESSAGE MISSING ÐContinued
Page 2228 of 2305
TEST ACTION APPLICABILITY
3 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any performance or bus related Engine DTCs present?All
Ye s!Refer to the Driveability category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Turn the ignition off to the lock position.
Replace and program the ECM per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ENGINE RPM MESSAGE, reset?All
Ye s!Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test Complete
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
63
TRANSMISSION - NAG1
ENGINE RPM MESSAGE ÐContinued
Page 2230 of 2305

TEST ACTION APPLICABILITY
2 Ignition on, engine not running.
With the DRBIIIt, read Transmission DTCs.
NOTE: If the DTC, CAN BUS CIRCUIT is present, perform diagnostics on
that symptom first.
Is the DTC, CAN BUS CIRCUIT, present?All
Ye s!Refer to the Transmission category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 3
3 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any Engine Temperature Sensor DTCs present?All
Ye s!Refer to the Driveability category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Replace and program the ECM per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ENGINE TEMP MESSAGE, reset?All
Ye s!Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test complete.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
65
TRANSMISSION - NAG1
ENGINE TEMP MESSAGE ÐContinued
Page 2234 of 2305

TEST ACTION APPLICABILITY
2 Ignition on, engine not running.
With the DRBIIIt, read Transmission DTCs.
NOTE: If the DTC CAN BUS CIRCUIT is present, perform diagnostics on
that symptom first.
Is the DTC, CAN BUS CIRCUIT, present?All
Ye s!Refer to the Transmission category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off to the lock position.
Disconnect the PCM/ECM harness connector(s).
Disconnect the TCM C2 harness connector.
Measure the resistance of the CAN C Bus + circuit between the PCM/ECM harness
connector and the TCM C2 harness connector.
Measure the resistance of the CAN C Bus - circuit between the PCM/ECM harness
connector and the TCM C2 harness connector.
Is the CAN C Bus + or - circuit open?All
Ye s!Repair the CAN C BUS + or - circuit for an open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any performance or bus related Engine DTCs present?All
Ye s!Refer to the Powertrain category and perform the appropriate
symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 5
5 Replace and program the PCM/ECM per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Start the engine.
With the brakes firmly applied, shift the gear selector into drive.
With the DRBIIIt, read Transmission DTCs.
Did the DTC, ENGINE CAN MESSAGE MISSING, reset?All
Ye s!Go To 6
No!Test Complete
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
6 If there are no possible causes remaining, view repair. All
Repair
Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
69
TRANSMISSION - NAG1
ENGINE TORQUE REDUCTION ÐContinued
Page 2246 of 2305

TEST ACTION APPLICABILITY
2 Ignition on, engine not running.
With the DRBIIIt, erase Transmission DTCs.
Raise the vehicle on the hoist.
Start the engine.
NOTE: This condition indicates a catastrophic transmission failure.
With the DRBIIItin Sensors, monitor the N2 and N3 Speed Sensors.
Firmly apply the brakes and place the gear selector in Drive (D).
Release the brakes and raise the engine RPM to allow the Transmission to upshift to
the 2-3 and 3-4 shift schedule.
CAUTION: BE SURE TO KEEP HANDS AND FEET CLEAR OF ROTATING
WHEELS.
Did either the N2 or N3 Speed Sensors display a RPM above 7700?All
Ye s!Go To 3
No!Go To 5
3 Remove the Transmission Oil Pan and inspect for debris or a plugged Transmission
Oil Filter.
Is there any debris, plugged Transmission Oil Filter, or signs of an Internal
Transmission problem?All
Ye s!Repair Internal Transmission as necessary. Pay particular atten-
tion to the Electrohydraulic Control unit. Refer to the Service
Information for proper repair procedures.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 4
4 If there are no possible causes remaining, view repair. All
Repair
Replace the Transmission Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
5 The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this
circuit.
Wiggle the wires while checking for shorts and open circuits.
NOTE: Check for any Technical Service Bulletins that may apply.
Were there any problems found?All
Ye s!Repair as necessary
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Test Complete.
81
TRANSMISSION - NAG1
INPUT SENSOR OVERSPEED ÐContinued