P0626

DTC P0626

CIRCUIT DESCRIPTION
The engine control module (ECM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator and fault indication. The generator field duty cycle signal circuit connects to the high side of the field winding in the generator. A pulse width modulated (PWM) high side driver in the voltage regulator turns the field winding ON and OFF. The ECM uses the PWM signal input to determine the generator load on the engine.

This allows the ECM to adjust the idle speed to compensate for high electrical loads.

The powertrain control module (PCM) monitors the state of the generator field duty cycle signal circuit. When the key in the ON position, with the engine OFF, the ECM should detect a duty cycle that is 0 percent.

The ECM monitors the PWM signal using a key ON test and a RUN test. During the tests, if the ECM detects an out of range PWM signal, a DTC will set.

CONDITIONS FOR RUNNING THE DTC
- No generator, CKP sensors, or CMP sensor DTCs are set.
- The engine is not running.
- The key is in the ON position.

CONDITIONS FOR SETTING THE DTC
The ECM detects a PWM signal greater than 5 percent for at least 15 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM will not illuminate the malfunction indicator lamp (MIL).
- The PCM will store the conditions present when the DTC set as Fail Records data only.
- The PCM will send a class 2 serial data message to the IPC and DIC to illuminate the charge indicator or display a charging message.

CONDITIONS FOR CLEARING THE MIL/DTC
- The conditions for setting DTC P0626 are not present.
- The DTC can be cleared by using the scan tool Clear DTC Information function.

TEST

Step 1:

Steps 2-5:

Steps 6-8: