Page 2217 of 2305

TEST ACTION APPLICABILITY
10 Turn the ignition off to the lock position.
Disconnect the ECM harness connector.
Measure the resistance between the CAN C Bus (+) and CAN C Bus (-) circuits in the
ECM harness connector.
Is the resistance 120.0 ohms 5.0 ohms?All
Ye s!Replace the ECM per the Service Information.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Go To 11
11 Turn the ignition off to the lock position.
Reconnect the ECM harness connectors.
Disconnect the SKREEM harness connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the SKREEM harness connector.
Is the resistance 120.0 ohms 5.0 ohms?All
Ye s!Replace the Sentry Key Remote Entry Module per the Service
Information.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+) and/or CAN C Bus (-) circuit for an
open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
12 Turn the ignition off to the lock position.
Disconnect the negative battery cable.
Disconnect the TCM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit at the TCM harness connector.
Is the resistance 60.0 ohms 5.0 ohms?All
Ye s!Replace the Transmission Control Module per the Service Infor-
mation.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+) and/or CAN C Bus (-) circuit for an
open.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
52
TRANSMISSION - NAG1
CAN BUS CIRCUIT ÐContinued
Page 2218 of 2305

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
Page 2219 of 2305
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
Page 2220 of 2305
Symptom:
CONTROL MODULE TCM IS NOT CODED
POSSIBLE CAUSES
TRANSMISSION CONTROL MODULE FLASH
TEST ACTION APPLICABILITY
1 View repair.All
Repair
Flash the Transmission Control Module to the proper level.
Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.
55
TRANSMISSION - NAG1
Page 2221 of 2305

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
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 2223 of 2305

Symptom:
ENGINE CAN MESSAGE MISSING
When Monitored and Set Condition:
ENGINE CAN MESSAGE MISSING
When Monitored: CAN Bus circuit error not present, 1 second after ignition on and not
in Park or Neutral, no System Overvoltage or System Undervoltage conditions present, or
transmission in Park or Neutral and engine RPM greater than 850 RPM.
Set Condition: This DTC is set if a CAN ID was not received in the required time, being
sent from the Engine Controller.
POSSIBLE CAUSES
CAN BUS +/- CIRCUIT OPEN
CAN BUS CIRCUIT DTC PRESENT
ENGINE DTCS PRESENT
ECM - ENGINE CAN MESSAGE MISSING
TCM - ENGINE CAN MESSAGE MISSING
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
58
TRANSMISSION - NAG1
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