| Subject: | Diagnostic Trouble Code C0201 Set and Stored in History |
| Models: | 2003 Chevrolet Express 2500/3500 Series Vans |
| 2003 Chevrolet Silverado 2500HD/3500HD Series Pickups |
| 2003 GMC Savana 2500/3500 Series Vans |
| 2003 GMC Sierra 2500HD/3500HD Series Pickups |
| with Manual HVAC (RPOs CJ3 or C42) |
When the above models require servicing that indicates to check for
any diagnostic trouble codes (DTC) in history, please note the following information.
You may find a false DTC C0201 (Open Relay , ABS) stored in history.
This code may be stored in error if the blower motor is set in position 3
or 4 and the ignition is turned OFF. When power is disconnected from the blower
motor at key off, the motor begins to coast down. During this period the motor
acts as a generator producing a small amount of electricity. This small voltage
is interpreted as an open relay and sets DTC C0201. On the following
key cycle, the relay is energized and passes it's test. The DTC
is then shifted to history and the customer never sees an ABS tell tale. ABS
will remain functional at all times.
No attempt should be made to correct this condition. If you encounter
DTC C0201 in history, it DOES NOT indicate any need to replace the
ABS module. If however, DTC C0201 is an active code and the I/P tell-tale
is illuminated, service is required. Follow the strategy-based diagnostics
for DTC C0201 as outlined in the Service Information.
This interaction will be corrected through software changes for the
2004 model year.
