Symptom:
ABS RR SENSOR MESSAGE
When Monitored and Set Condition:
ABS RR SENSOR MESSAGE
When Monitored: Valid ABS CAN messages received at least once and the CAN Bus
circuit, ABS CAN Message Missing, ABS CAN Message Incorrect are not active
Set Condition: ABS signal9wheel speed rear right9not valid or ABS has detected a sensor
failure.
POSSIBLE CAUSES
CAN BUS CIRCUIT DTC PRESENT
ABS DTCS PRESENT
ABS CONTROL MODULE - ABS RR SENSOR MESSAGE
TCM - ABS RR SENSOR MESSAGE
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 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
44
TRANSMISSION - NAG1
TEST ACTION APPLICABILITY
3 Ignition on, engine not running.
With the DRBIIIt, read ABS DTCs.
Are there any ABS DTCs present?All
Ye s!Refer to the BRAKE 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 the ABS Control Module per the Service Information.
With the DRBIIIt, erase Transmission DTCs.
Road test the Vehicle.
With the DRBIIIt, read Transmission DTCs.
Does the DTC, ABS RR SENSOR 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.
45
TRANSMISSION - NAG1
ABS RR SENSOR MESSAGE ÐContinued
Symptom:
ACCEL PEDAL SENSOR CAN MESSAGE INCORRECT
When Monitored and Set Condition:
ACCEL PEDAL SENSOR CAN MESSAGE INCORRECT
When Monitored: When a valid Accelerator Pedal Position (APP) CAN Message Received
at least once and the DTCs, CAN Bus Circuit, Engine CAN Message Missing and Engine
CAN Message Incorrect are not active.
Set Condition: Accelerator Pedal Position (APP) Message not valid or a ECM Engine
Sensor DTC detected.
POSSIBLE CAUSES
CAN BUS CIRCUIT DTC PRESENT
ENGINE ACCEL PEDAL DTCS PRESENT
ENGINE COMMUNICATION DTCS PRESENT
INTERMITTENT WIRING AND CONNECTORS
ECM - ACCEL PEDAL SENSOR CAN MESSAGE INCORRECT
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
46
TRANSMISSION - NAG1
TEST ACTION APPLICABILITY
2 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 With the DRBIIIt, read Transmission DTCs.
Is the DTC Accel Pedal Sensor CAN Message Incorrect displayed as ACTIVE?All
Ye s!Go To 4
No!Go To 8
4 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any Engine bus related DTCs present?All
Ye s!Refer to the Communication category and perform the appropri-
ate symptom.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 5
5 Ignition on, engine not running.
With the DRBIIIt, read Engine DTCs.
Are there any Accel Pedal 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 6
6 Replace the Transmission Control Module.
NOTE: Perform the transmission verification test.
Did the DTC9Accel Pedal Sensor CAN Message Incorrect9reset?All
Ye s!Go To 7
No!Test Complete.
7 If there are no possible causes remaining, view repair. All
Repair
Replace the Engine Control Module.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
8 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.
47
TRANSMISSION - NAG1
ACCEL PEDAL SENSOR CAN MESSAGE INCORRECT ÐContinued
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 With the DRBIIIt, read the active and stored DTCs for all modules that use CAN Bus
communication.
NOTE: Due to capabilities of certain controllers that use the CAN Bus, not
all modules report CAN Bus DTCs.
NOTE: If a total CAN Bus failure transpires, there will be multiple CAN Bus
DTCs present in many modules. If the other modules are reporting Trans-
mission CAN Bus messages ONLY, answer No for the following question.
Are other modules reporting active or stored CAN Bus communication DTCs?All
Ye s!Go To 3
No!Go To 12
3 Turn the ignition off to the lock position.
Disconnect the negative battery cable.
While back probing, measure the resistance between the CAN C Bus (+) and the CAN
C Bus (-) in the selected control module harness connector.
NOTE: Termination of the CAN Bus is located in the ECM and SKREEM.
Both modules use a 120.0 ohm resistor for termination of the CAN Bus. A
properly terminated CAN Bus will read 60.0 ohms 5.0 ohms.
Pick the one that best describes your readings:All
60.0 ohms 5.0 ohms.
Go To 4
120.0 ohms 5.0 ohms.
Go To 10
Less than 60.0 ohms
Go To 8
49
TRANSMISSION - NAG1
CAN BUS CIRCUIT ÐContinued
Symptom:
CAN MESSAGE FROM ECM FROM SLA
When Monitored and Set Condition:
CAN MESSAGE FROM ECM FROM SLA
When Monitored:
Set Condition: CAN Bus message received from the Shift Lever Assembly are incorrect.
POSSIBLE CAUSES
CAN BUS CIRCUIT DTC PRESENT
SHIFT LEVER DTCS PRESENT
OPEN CAN BUS CIRCUITS AT SHIFT LEVER
SHIFT LEVER ASSEMBLY
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 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.
No!Go To 3
53
TRANSMISSION - NAG1
TEST ACTION APPLICABILITY
3 Ignition on, engine not running.
With the DRBIIIt, read Shift Lever DTCs.
Are there any Shift Lever DTCs present?All
Ye s!Refer to the Shift Lever category and perform the appropriate
symptom.
No!Go To 4
4 Turn the ignition off to the lock position.
Disconnect the Shift Lever harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Shift Lever harness connector.
Is the resistance 60 ohms, 3.0 ohms?All
Ye s!Replace the Shift Lever Assembly per the service information.
No!Repair the CAN Bus (+) or the CAN Bus (-) circuit for an open.
54
TRANSMISSION - NAG1
CAN MESSAGE FROM ECM FROM SLA ÐContinued
Symptom:
ENGINE CAN MESSAGE INCORRECT
When Monitored and Set Condition:
ENGINE CAN MESSAGE INCORRECT
When Monitored: CAN-ID received at least once and CAN Bus Circuit DTC is not active.
Set Condition: DTC Detected if the number of bytes incorrect for CAN ID.
POSSIBLE CAUSES
ENGINE DTCS PRESENT
ECM - ENGINE CAN MESSAGE INCORRECT
TCM - ENGINE CAN MESSAGE INCORRECT
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 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 3
56
TRANSMISSION - NAG1