Mike's Workshop Manuals
: Service manuals for every vehicle
Home
>>
Chevrolet
>>
2002
>>
Chevy Express G2500, Van Cargo Extended, 6.5 F
>>
Repair and Diagnosis
>>
Electrical
>>
Charging Systems
>>
Charging System
>>
Diagnostic Tests
>>
DTC P1638: Pulse Width Modulated Signal Out Of Range
>>
Conditions For Setting DTC
Conditions For Setting 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.