PCM Issues

[timgco]

Anyone know of a TSB on the Power Control Module for 05's?

That code got thrown 4 times and my truck had no power. you couldn't even push on the gas pedal without the truck killing. It did this at high altitude and got a little better as I got down to lower altitude. Any ideas? Dealer sounds to be stumped and I don't want to deal with this again. Anyone else have this issue with an 05?

[timgco]

Anyone know of a TSB on the Power Control Module for 05's?

That code got thrown 4 times and my truck had no power. you couldn't even push on the gas pedal without the truck killing. It did this at high altitude and got a little better as I got down to lower altitude. Any ideas? Dealer sounds to be stumped and I don't want to deal with this again. Anyone else have this issue with an 05?

[PARAGON]

Tim,

When the truck gets a code and goes to reduced engine power, the computer is in complete control and you really can't overcome it without shutting it down and restarting. The reduced engine power is a safety precaution of the computer and is not really indicative of a major issue by itself.

You might have a voltage problem and I think a few, maybe even '05s have had the ignition replaced.

I was having voltage problems due to the battery and I would get the "reduced engine power" deal but I would be sitting in my driveway and just couldn't get going.

[LasVegas]

HummerTech could probably shed more light on this but getting ready to install my turbocharger I've done quite a bit of research on PCMs. First, is it running okay now without them fixing anything...just clearing the codes? Second, exactly what were the codes? I can research the diagnostics for you if I know the codes. Third, are you saying the dealer didn't do anything and isn't going to do anything?? If so, that's crazy. If it happened once, it's going to happen again. If nothing else, they should replace the PCM & check all communications. The PCM gathers all the information from the various sensors, etc. & adjusts a number of settings continuously. Either a sensor(s) is defective, communications lost, or the PCM is defective. They need to fix this for you.

[LasVegas]

Could you have done anything at MOAB to cause this? <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Verify that the engine is not in a torque reduction mode. The PCM turns certain injectors OFF or reduces the engine timing when the PCM detects an over torque condition or an abusive maneuver. </div></BLOCKQUOTE>

[timgco]

Hey Jonahs, The dealer still has it and is trying to duplicate the problem and can't. Suprise! So it has 95 miles since tha last trouble code was flagged. He is now telling me that my Oxegen sensors all falgged. how many are there and wher are they at?

[LasVegas]

There are 4 oxygen sensors. Two on each exhaust side. One before the catalytic converter & one after it. They're easy to see & get to. Did they get wet???? They're basically waterproof but the connectors may have taken on water.

[LasVegas]

It would be impossible for all 4 sensors to fail & send a code at the same time unless it was a common problem like water or something. It sure explains the symptoms though. The 02 sensors are detecting oxygen in the exhaust & sending the signal to the PCM that is then adjusting air/fuel mixture. This is happening very quickly and continuously except in warm up mode (about 30 - 60 seconds after startup) & at wide open throttle. If this ever happens again, try absolute wide open throttle. The PCM then ignores the oxygen sensors and takes over control of the mixture (open loop).

[LasVegas]

Absent water or some other (don't know what it would be) problem, it could be the 02 circuit within the PCM itself sending the codes. It has to be a common problem because 4 02 sensors failing at the same time just doesn't happen. It should make it easier for the dealer to pin down.

[LasVegas]

Tim...let me know the code numbers. They should be somewhere between P0131 and P0160

[timgco]

replaced Evap Canister.

[partsguy]

wasn't red, was it?Code M0254.
Trans to M0254= you had too much fun so the
PCM depowers the bcm to make you
DFM = Damn fing Mad.
Glad everythings well

[Hummertech]

If your dealer can't duplicate your problem, they can send you home with a black box that is hooked up to your truck called a vehicle data recorder. It will have a button on it that you push when it acts up. They can do that for you.

[LasVegas]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by timgco:
replaced Evap Canister. </div></BLOCKQUOTE>Glad they found the problem Tim. Hopefully that's the end of it.