PCM possibly bad, anything else to check?
10-03-2009, 04:37 AM
#11
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NO. The PATS will not allow the vehicle to start. Before you replace th PCM try this. Move the wire harness that passes close to the AC accumulator tank away from it. It has been known to cause problems in the earlier years.
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10-03-2009, 12:26 PM
#12
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I've heard about the accumulator problem, but had forgotten to check it. Thanks for the reminder.
Will I have to take the truck to the dealership or can I just take the PCM (since the truck will not be running...)? Exactly what has to be reprogrammed - the new PCM to accept the PATS codes, or the module that holds the PATS codes to accept the new PCM? Or something else? The supplier of the PCM says it does not have to be programmed to my particular VIN. It is the same part # of my current PCM, same year, engine, tranny.
Will I have to take the truck to the dealership or can I just take the PCM (since the truck will not be running...)? Exactly what has to be reprogrammed - the new PCM to accept the PATS codes, or the module that holds the PATS codes to accept the new PCM? Or something else? The supplier of the PCM says it does not have to be programmed to my particular VIN. It is the same part # of my current PCM, same year, engine, tranny.
10-03-2009, 02:16 PM
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The way I understand things the old PCM VID info has to be downloaded from the old PCM and then uploaded into the new PCM. I believe that the Dealer only needs both PCMs. Call the dealer to be sure.
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10-08-2009, 09:41 PM
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I found a vacuum leak! I discovered that the hard plastic tube that connects to the rubber PCV hose is unhooked at the back of the engine. But I can't find where it is disconnected from. I have felt all around the back of the TB/intake, looked with a mirror, and cannot find any open ports to plug it in. Upon closer inspection, a short rubber connector on the end of the plastic pipe appears to be torn? Anybody have any pictures or diagrams of where this goes? I'd even settle for a really descriptive answer...
10-12-2009, 08:57 AM
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The truck is running smoothly once again!
The rubber connector was a straight reducer type fitting - small on one end, large on the other. Dealer was the only carrier, but wasn't open when I could stop by. So I made my own with a piece of heater hose, a hose clamp and a piece of 3/8" hose.
It was very interesting that with a large vacuum leak, the PCM would not let the truck go into closed loop mode, and would also not report the oxygen sensor values. I incorrectly assumed the PCM was possibly faulty, but now I think that is how the logic is setup in the PCM. Once the leak was repaired, the oxygen sensor values appeared correctly, and closed loop was achieved after warmup. I would love to know all the logic steps programmed into the PCM.
The rubber connector was a straight reducer type fitting - small on one end, large on the other. Dealer was the only carrier, but wasn't open when I could stop by. So I made my own with a piece of heater hose, a hose clamp and a piece of 3/8" hose.
It was very interesting that with a large vacuum leak, the PCM would not let the truck go into closed loop mode, and would also not report the oxygen sensor values. I incorrectly assumed the PCM was possibly faulty, but now I think that is how the logic is setup in the PCM. Once the leak was repaired, the oxygen sensor values appeared correctly, and closed loop was achieved after warmup. I would love to know all the logic steps programmed into the PCM.