P0622 Generator Field F control circuit problem

TLEE2323

MEMBER
2006 CHEVROLET TRAILBLAZER
0.6L
6 CYL
4WD
AUTOMATIC
142,000 MILES

Today this code was pulled on my vehicle. Last week when trying to restart the vehicle it began to suddenly shake(the whole vehicle) I turned it off, waited 30 sec, restarted and it did it again. Then I waited 1-2 min and it has not happened since.

Online reports say this might be an alternator issue. Could this be related to "air bag warning light" and code B1000 ECU malfunction or running lights that go out in the rain?

I am wondering if all of this is connected to a wiring problem or short somewhere. Or, they might all be unrelated. Can you help?

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning

the simple answer to your issue is no. The code is not the cause of your issue but this is the code and the description.

Roy

DTC P0622

CIRCUIT DESCRIPTION
The powertrain control module (PCM) uses the generator field duty cycle signal circuit to monitor the duty cycle of the generator. 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 PCM uses the PWM signal input to determine the generator load on the engine. This allows the PCM to adjust the idle speed to compensate for high electrical loads.

The PCM monitors the state of the generator field duty cycle signal circuit. When the key is in the RUN position, and the engine is OFF, the PCM should detect a duty cycle near 0 percent. However, when the engine is running, the duty cycle should be between 5-100 percent. The PCM monitors the PWM signal using a key ON test and a RUN test. During the tests, if the PCM detects an out of range PWM signal, DTC P0622 will set. When the DTC sets, the PCM will send a class 2 serial data message to the instrument panel cluster (IPC) to illuminate the charge indicator.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0622 Generator F-Terminal Circuit

CONDITIONS FOR RUNNING THE DTC

Key ON Test
No generator, crankshaft position (CKP) sensors, or camshaft position (CMP) sensor DTCs are set.
The key is in the RUN position.
The engine is not running.
Run Test
No generator, CKP sensors, or CMP sensor DTCs are set.
The engine is less than 3,000 RPM.
CONDITIONS FOR SETTING THE DTC
During the ignition ON test, the PCM detects a PWM signal is out of range.
During the RUN test, the PCM detects a PWM signal less then 5 percent for more than 6 seconds.
ACTION TAKEN WHEN THE DTC SETS
The PCM will store the conditions present when the DTC set as Fail Records data only.
The malfunction indicator lamp (MIL) will not illuminate.
CONDITIONS FOR CLEARING THE DTC
The Conditions for Setting the DTC are no longer present.
A history DTC will clear after 40 malfunction-free ignition cycles.
The PCM receives the clear code command from the scan tool.
TEST