Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
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This step tests for valid system power moding in all ignition switch positions.
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The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
Step | Action | Yes | No | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications | ||||||||||
Does the scan tool communicate with the BCM? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Devicein Data Link Communications | |||||||||||
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Important: Important: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
Does the Class 2 Power Mode parameter reading match the ignition switch position for all switch positions? | Go to Step 4 | Go to Power Mode Mismatch in Body Control System | |||||||||||
4 | Select the BCM display function on the scan tool. Does the scan tool display any DTCs? | Go to Step 5 | Go to Symptoms - Retained Accessory Power | ||||||||||
Does the scan tool display any DTCs which begin with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 6 | |||||||||||
6 | Does the scan tool display any of the following DTCs?
| Go to Diagnostic Trouble Code (DTC) List in Body Control System | Go to Step 7 | ||||||||||
7 | Select the PCM display function on the scan tool. Does the scan tool display DTC P0562? | Go to 2.2L or 2.4L in Engine Electrical | Go to Symptoms - Retained Accessory Power |
