P1638H - Anyone know what this code is?
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Joined: Mar 2002
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From: Kansas City MO
P1638H - Anyone know what this code is?
It showed up along with P0300H on my ill-fate trip to the drag strip posted below - "Check Engine Light with 100 shot"
Thanks for any help.
Kurt
Thanks for any help.
Kurt
Le Mans Master
Joined: Jan 2001
Posts: 6,429
Likes: 1
From: God's Replica
Re: P1638H - Anyone know what this code is? (wallstAL)
DTC P1638
Circuit Description
The 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 percent and 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 P1638 will set. When the DTC sets, the PCM will send a class 2 serial data message to the IPC to illuminate the Charge System Fault message.
Conditions for Running the DTC
Key ON Test
No generator, CKP sensors, or 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 3000 RPM.
Conditions for Setting the DTC
During the key ON test, the PCM detects a PWM signal greater than 65 percent for at least 5 seconds. OR
During the RUN test, the PCM detects a PWM signal less 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.
Conditions for Clearing the MIL/DTC
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear DTC Information function. :cheers:
Circuit Description
The 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 percent and 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 P1638 will set. When the DTC sets, the PCM will send a class 2 serial data message to the IPC to illuminate the Charge System Fault message.
Conditions for Running the DTC
Key ON Test
No generator, CKP sensors, or 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 3000 RPM.
Conditions for Setting the DTC
During the key ON test, the PCM detects a PWM signal greater than 65 percent for at least 5 seconds. OR
During the RUN test, the PCM detects a PWM signal less 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.
Conditions for Clearing the MIL/DTC
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear DTC Information function. :cheers:
Thread Starter
Advanced
Joined: Mar 2002
Posts: 72
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From: Kansas City MO
Re: P1638H - Anyone know what this code is? (intel55)
Hmmm, interesting. I've been noticing that my voltage is running lower than it usually does. And at the track, I do turn the key on (not the engine) and run the heater to cool down the engine. This might not be such a good idea. I also think this guy wired my NOS system screwy.
Thanks again.
Kurt
Thanks again.
Kurt
Le Mans Master
Joined: Jan 2001
Posts: 6,429
Likes: 1
From: God's Replica
Re: P1638H - Anyone know what this code is? (WorldofOutlaws)
I have a better way to cool down your engine. Anothe forum member awhile ago gave me this diagram and stuff so I can make my HI speed fans go on whenever I want them.
I can probably find the zip file that has all the directions to make it. Cost is about $20 for parts and the switch can be mounted anywhere. I put mine in the ashtray. I sit in the lanes and flip the switch and the HI speed fans sing :D
I can probably find the zip file that has all the directions to make it. Cost is about $20 for parts and the switch can be mounted anywhere. I put mine in the ashtray. I sit in the lanes and flip the switch and the HI speed fans sing :D
