Ok, if you didn't read this before I just purchased 97 C5. I like the pop up headlights, goes well with my 72 conv. I have rreplaced both nylon gears in the headlamp motors. Toke out the Duralast battery and put in an Optima yellow top. After reassembling the headlight and cleaning off the HL module in the passenger side the lights work sometimes and sometimes not. when pulling the stalk back to pass the brights come on but that is it. The headlamps come up extremely quiet when they do decide to come up. I cleared all the codes and went for a ride. Did the diagnostics and have one pcm P1571 H. all other codes remained clear. I am thinking it is either the ground for the light system or the stalk on the wheel. If it was the module I don't think they would work at all not just some of the time. Any ideas? I don't want to just blindly start replacing parts in hope that is it. I now apologize to my 72 vette for all the times I cussed at u for having slow headlights due to the cam producing lower vacuum. any experience / help would be appreciated!

 

P1571
The PCM supplies 5.0 volts on the Desired Torque circuit to the Electronic Brake and Traction Control Module (EBTCM). The EBTCM toggles this 5.0 volt signal to a ground in order to produce a duty cycle signal. The signal is proportional to the amount of engine output torque reduction requested by the EBTCM. The EBTCM supplies this signal when it detects a wheel slip. In order to reduce engine output torque, the PCM reduces the amount of spark advance and in some cases the PCM disables a number of fuel injectors. This diagnostic test checks for a Desired Torque signal failure. If the PCM does not receive the Desired torque signal this DTC sets.

CONDITIONS FOR SETTING THE DTC

The traction control has not failed.
The engine speed is greater than 500 RPM for 20 seconds.
The desired torque signal is not received by the PCM for 3 seconds.
ACTION TAKEN WHEN THE DTC SETS

The PCM stores the DTC information into memory when the diagnostic runs and fails.
The Malfunction Indicator Lamp (MIL) will not illuminate.
The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC

A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
The PCM battery voltage is interrupted.
Use a scan tool in order to clear the MIL/DTC.
DIAGNOSTIC AIDS

IMPORTANT: Do not perform this diagnostic procedure if the customer's concern is not related to the ABS and/or the Traction Control system(s).

The following may cause an intermittent:

Mis-routed harness
Rubbed through wire insulation
Broken wire inside the insulation

The p1571 has nothing to do with the headlights, see above. I suggest you check all the fuses. If all are good, get a wiring diagram for the headlamps and actuators.

 

waiting on my service manuals to get here then when I get back from vacation I plan to check every ground I can access and clean and dress with dielectric. then see where I am at. Thanks for the info. I guess I will just have to wait and be patient. I just hope I can pass the title inspection tomorrow so I can quit driving around on the guys plates I bought it from. Ohio is pretty harsh on their out of state car inspections. I got a 78 jeep cj5 from MI once and they were complete aholes! As far as the fuses go that the the first thing. I checked & cleaned posts on every single fuse I have. It works some of the time it has to be a ground issue or a short in one of the million wires on the car or a short in the switch itself. How hard is it to change the switch on the column?