Cruise Module Diagnosis

[steelmanwy]

Purchased a cruise module and switchpod from a user on the forum quite a while ago, but just recently got the PCM flashed at the closest Saturn dealer (375 miles, don't make it down that way very often).

The seller said would work on 96-99 models, not sure what year car it came from. Should the module interchange for those year s-models?

With a whole lot of contortion, cussing and skinned elbows, I eventually tested the voltage across the pink and black wires at the wire harness to the module and got 12 volts, verifying that the power portion of the switchpod is functional. Will the set/coast, resume/accel functions show a voltage when the buttons on the switchpod are pushed? Just to make sure the switch is all OK.

I removed the cruise module to see if I could find a problem. Took the thing apart and saw no burn marks on the control board, belt was intact, continuity through motor, gears and linkage screw turned freely. Anyone know of any other diagnosis on a cruise module? Or, do you all think I should just try another used module?

[OldNuc]

Find a local shop with a scanner. There are codes for cruise functions. P1580 to P1583 and P0565. These do not set either the SES light or the Service light. These codes are only active to be set if the PCM has the cruise enabled. If you clear your codes by pulling the PCM B fuse for a couple of minutes and then go for a drive and play withthe cruise buttons. Then go read the codes.

Did you tell the dealer to enable the cruise control? Or just ask for a reflash?

They have to set the options on a screen when they do a flash and if all they did was download the original flash then all you got was your original factory installed options.

This is the screen they have to use. Any shop with a Tech -2 (GM Dealer) can turn on the cruise.


The parts you have should work....If enabled.

[steelmanwy]

The codes will set if there is an error in the cruise diagnostics, but will not turn on the trouble lights, am I thinking corretly?

I asked them to add cruise and work order specifies that as well.

Will scan codes tonight and see what's up.

[OldNuc]

If cruise is not enabled in the PCM then there will be no codes. If cruise is enabled in the PCM and the cruise does not function then 1 or more of those codes will set.

You will have to locate a real scanner to read these codes. If there are none pull the cruise fuse and go for a drive at 50 mph or a bit over and that should set one on power failure. Then you know its a cruise or wiring problem.

[steelmanwy]

While I had the module out, I went for a drive and the SES light came on. My scanner was not able to read any codes, but I cleared the code memory anyway. Reinstalled the module, SES light did not come on, still no engagement of cruise. Tried to read codes again and scanner did not read any codes.

I'm assuming that since the SES light came on while the module was out and went off after it was reinstalled that the cruise is indeed enabled in the PCM. I'm also assuming that since my scanner would not read the code for the cruise power issue, that it will not read the codes for the set / accel issues either. Not sure what to do next, I guess go to a shop and see if they can pull any codes.

[madpogue]

I can't say with absolute certainty, but I would think your experiment would have turned on the "Wrench" light, not the SES.

[OldNuc]

All codes related to the Cruise control system do not turn on either light. That info is right out of the 98-99 FSM, 96 and 97 may have been slightly different but they would have set the Service light as the SES is reserved by EPA mandate for emission related events. The fact you received a code is interesting. Would have been interesting if you could have extracted the code. The P0565 and P0571 do not turn on any light either. Those are the buttons and brake switch.

Without the code you received I have no idea what happened. It does tend to indicate a possible problem. Try pulling the Cruise fuse instead and see if that sets an SES light.

[steelmanwy]

Originally Posted by madpogue

I can't say with absolute certainty, but I would think your experiment would have turned on the "Wrench" light, not the SES.

Yes, the Service (wrench) light, not the SES, was lit up. Sorry for my confusion...

[OldNuc]

Leave it connected at the module and pull the fuse.

[mrbios]

Old post but my 1997 SW2 started having a problem a few months ago where the Cruise Control would not engage. I can confirm there is no wrench icon lit up and also no SES - Service Engine Soon icon lit up either. Car is in good running condition with 172K miles. I am the original owner.

Recently, I made a video after the charcoal canister purge valve acted up after starting the car and used a code scanner to record what code that condition generates and I noticed another code: P1583 "Cruise control system, direction circuit voltage high." and I thought that makes sense since the cruise which I use all the time on the highway and never had any problems for decades now fail to engage sometimes. When it does engage it works perfectly allowing me to speed up or slow down so it can't be the Set or Accel buttons because they respond perfectly. Now I suspect the cause is that whatever component monitors the the engine RPM or something like that is not getting a proper reading aka voltage that is outside of the max range. It is not easy to find info on cruise control codes even for other car brands.

NOTE: I tried switching the ON/OFF switch off and on again while driving then try to engage cruise with no luck. I also pulled over and turned the car off then restarted with no luck. Then randomly it works fine again.