NGC

U1113-LOST A/C PRESSURE MESSAGE





For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
With the ignition on, battery voltage between 9 and 16 volts, and engine run time greater than 3 seconds.

- Set Condition:
The PCM either doesn't receive a bus message or receives an implausible bus message from the Body Control Module (BCM).





Refer to Communications Test for this DTC and/or Manufacturer Code Charts for diagnostic procedures and for further possible causes.

Theory of Operation

The PCM receives:

- Wheel speed and wheel distance CAN bus messages from the Anti-lock Brake module.

- A/C Pressure, Ambient Air Temperature and Fuel Level CAN bus messages from the Body Control Module.

Diagnostic Test

1. ACTIVE DTC
NOTE: For vehicle communication problems, use the scan tool to refer to the Network Review Screen. The screen depicts a high level view of the vehicle network. Fault and problem areas appear in red. Selecting any of the network components allows access to the source of the problem.

NOTE: Diagnose and repair any related sensor or communication DTCs in the Body Control Module (BCM) before continuing with this test.

Start the engine and allow it to reach operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With a scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Refer to Communications Test for this DTC and/or Manufacturer Code Charts for diagnostic procedures and for further possible causes.

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking For An Intermittent DTC
- Perform the PCM Verification Test. Powertrain Verification Test