No Response From ITBM (Integrated Trailer Brake Module)

NO RESPONSE FROM ITBM (INTEGRATED TRAILER BRAKE MODULE)

For a complete wiring diagram, refer to the Wiring Information.









Diagnostic Test

1. TEST FOR INTERMITTENT CONDITION

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

1. Turn the ignition on.

NOTE: Make sure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

2. With the scan tool, read the module status.

NOTE: Check the BCM for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

- The no response condition is not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.

No

- Go To 2

2. CHECK THE (A400) FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT
1. Turn the ignition off.
2. Disconnect the Integrated Trailer Brake Module (ITBM) C1 harness connector.
3. Turn the ignition on.
4. Using a 12-volt test light connected to ground, check the (A400) Fused B(+) circuit.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the (A400) Fused B(+) circuit for an open or short.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.

3. CHECK THE (F944) FUSED IGNITION SWITCH OUTPUT (RUN-START) CIRCUIT FOR AN OPEN OR SHORT
1. Using a 12-volt test light connected to ground, check the (F944) Fused Ignition Switch Output (Run-Start) circuit.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the (F944) Fused Ignition Switch Output (Run-Start) circuit for an open or short.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.

4. CHECK THE (Z910) GROUND CIRCUITS FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the ITBM C3 harness connector.
3. Using a 12-volt test light connected to 12-volts, check the (Z910) Ground circuits.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the (Z910) Ground circuits for an open.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.

5. CHECK THE (D197) CAN C(+) BUS CIRCUIT FOR AN OPEN
1. Disconnect the Star Can C IP C4 harness connector.
2. Measure the resistance of the (D197) CAN C Bus (+) circuit between the Star Can C IP C4 harness connector and the ITBM C3 harness connector.

Is the resistances below 5.0 Ohms?

Yes

- Go To 6

No

- Repair the (D197) CAN C(+) Bus circuit for an open.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.

6. CHECK THE (D196) CAN C(-) BUS CIRCUIT FOR AN OPEN
1. Measure the resistance of the (D196) CAN C Bus (-) circuit between the Star Can C Dash C2 harness connector and the DTCM C1 harness connector.

Are the resistances below 5.0 Ohms?

Yes

- Replace the Integrated Trailer Brake Module (ITBM). Integrated Trailer Brake Module - Removal.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.

No

- Repair the (D196) CAN C(-) Bus circuit for an open.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.