1999 Explorer ECU
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1999 Explorer ECU
On my 99 Explorer the AC went out because the brain thinks that the throttle is always all the way on or whatever and won't let the AC kick on, it just blows hot air. A mechanic looked at it and said the AC unit works fine though. <br>My question is if I get a new ECU does it have to be reprogrammed or something or do you just put it in and it's good to go?
Thanks.
Thanks.
Logistics Pro
Joined: Jun 2009
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From: Cedar Rapids, IA
How did someone decide it thinks you're wide open throttle all the time? If the WOT parameter is set in the datastream, the issue likely is not the PCM but rather the Throttle Position Sensor. I'd be more inclined to suspect the pressure switch on the A/C is faulty, the charge is not correct, or the compressor clutch is not working properly. If the PCM thinks the throttle is WOT all the time, you'd should notice some driveability issues (poor fuel economy, firm, high rpm shifts of the transmission, smelly exhaust, etc.).
-Rod
-Rod
Logistics Pro
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From: Cedar Rapids, IA
Then I'd (still) be curious to understand how someone came to the conclusion the A/C thinks the throttle is wide open. I'd hate for you to install a new PCM only to find that wasn't the issue.
-Rod
-Rod
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A mechanic looked at it. Said when they disconnected the battery, the code cleared out and the air would work for a few seconds. As soon as the accelerator was used it cut off. The car is running ok, the mechanic said the ECM continues to read the throttle is wide open although it is not. He checked the a/c parts individually and everything was working properly. They attempted to by-pass the ECM and the air still wouldn't kick on. All shifting and idling are appropriate. The mechanic felt a new ECM would fix the problem.
I have also seen that the throttle position sensor or a/c pressure switch may be the problem. Relay is good. Just can't get compressor to engage. Any thoughts?
I have also seen that the throttle position sensor or a/c pressure switch may be the problem. Relay is good. Just can't get compressor to engage. Any thoughts?
Last edited by zzzonked; Jul 3, 2011 at 09:40 PM. Reason: additional info
Cargo Master
Joined: Aug 2003
Posts: 3,263
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From: BC Canada
Either use an analog meter and set the Throttle voltage at idle (.96vdc) then watch the needle climb steadily as throttle is opened, or connect a scanner and watch the throttle opening on the graph... any jumping or skipping will require a replacement TPS...
BTW, shorting out any input/output for the CPM can spell DOOOM $$$! Philip
BTW, shorting out any input/output for the CPM can spell DOOOM $$$! Philip
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