C2129-17

C2129-17 BATTERY VOLTAGE - CIRCUIT VOLTAGE ABOVE THRESHOLD





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

Theory of Operation

The Integrated Trailer Brake Module (ITBM) communicates with the vehicle through the high speed CAN B bus. The ITBM monitors the Brake Pedal Status and Vehicle Speed. It also outputs the Trailer Status, Gain Setting, and Brake Output Power to the vehicle. The ITBM connects to the electric trailer brakes through the 7-Way connector and controls the brake force through a Pulse Width Modulating (PWM) duty cycle.

NOTE: If there is no trailer connected there will be NO Pulse Width Modulating (PWM) signal.

The ITBM controls the PWM output to the trailer brakes in two ways. The first occurs while the brake pedal becomes active, the PWM is proportional to the rate of deceleration measured by the accelerometer inside the ITBM. The second is the manual lever (squeeze switch) on the ITBM that can be controlled by the driver. If both are active, the greater of the two, in terms of PWM output, will prevail.

- When Monitored:
Ignition on and no system undervoltage DTC active.

- Set Condition:
If the sensed ignition voltage is greater than 16.5 volts for 100 msec.





1. CHARGING SYSTEM DTCs PRESENT
1. Ignition on, engine not running.
2. With the scan tool, read DTCs in the PCM.

Are there any Charging System or related voltage DTCs present?

Yes

- Perform the appropriate Charging System DTC diagnostic procedures before continuing with this test. Testing and Inspection.

No

- Go To 2

2. DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, record and erase DTCs.
3. Turn ignition off to the lock position.
4. Start the engine.
5. With the scan tool, read DTCs.

Is the status Active for this DTC?

Yes

- Replace the Integrated Trailer Brake Module (ITBM). Integrated Trailer Brake Module - Removal.

No

- Test complete, the condition or conditions that originally set this DTC are 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.
- Perform the ITBM VERIFICATION TEST. ITBM Verification Test.