LaCrosse V6-3.6L (2007)
Step 16 - Step 20
The numbers below refer to the step numbers on the diagnostic table.
2. A partial loss of communication in the class 2 serial data circuit uses a different procedure than a total loss of communication of the class 2 serial
data circuit.
4. The following DTCs may be retrieved with a history status. These DTCs are not the cause of the present condition.
* U1300
* U1301
* U1305
6. A State of Health DTC with a history status may be present along with a U1000 or U1255 with a current status. This indicates that the malfunction
occurred when the ignition was ON.
10. Normal class 2 serial data communication cannot take place until the power mode master (PMM) module sends the appropriate power mode
message. If the PMM does not send a wake-up message, other modules on the class 2 serial data circuit may not communicate.
12. This step uses the loss of communications with a class 2 serial data circuit to locate the probable malfunction.
On vehicles equipped with a digital radio receiver (DRR), the DRR must be isolated from the sensing and diagnostic module (SDM) to evaluate
the condition of that class 2 serial data circuit branch.
The following modules communicate on the class 2 serial data circuit:
* Driver information center (DIC)
* DRR
* Electronic brake control module (EBCM)
* Instrument panel cluster (IPC)
* Head-up display (HUD)
* HVAC
* Powertrain control module (PCM)
* Radio
* Vehicle communication interface module (VCIM)
* SDM
17. If there are no current DTCs that begin with the letter "the communication" concern has been repaired.
18. The communication concern may have prevented diagnosis of the customer complaint.
