Circuit Description
Important: Always check the generator for output before assuming that a grounded L terminal circuit has damaged the regulator. Refer to Generator Replacement .
When operating normally, the generator indicator lamp will come ON when the ignition switch is in the ON position and go out when the engine starts. If the lamp operates abnormally or if an undercharged or overcharged battery condition occurs, the following procedure may be used to diagnose the charging system. Remember that an undercharged battery is often caused by accessories being left ON overnight or by a defective switch that allows a lamp, such as a trunk or glove box lamp, to stay ON.
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 malfunction of the serial data circuits. The specified procedure will determine the particular condition.
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The presence of DTCs may be related to an engine electrical condition. The specified procedure will compile all the available information before tests are performed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Perform the Battery Inspection/Test. Refer to Battery Inspection/Test . Does the battery pass the test? | Go to Step 2 | -- |
Install a scan tool. Does the scan tool power up? | Go to Step 3 | Go to Scan Tool Does Not Power Up in Data Link Communications | |
3 |
Does the scan tool communicate with the ECM? | Go to Step 4 | Go to Scan Tool Does Not Communicate with Component in Data Link Communications |
4 | Select the ECM. Display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 1.6L, or Diagnostic Trouble Code (DTC) List in Engine Controls - 1.8L, or Diagnostic Trouble Code (DTC) List in Engine Controls - 2.0L |
