1994 Ford Bronco - replacing PCM

JOHN PETERSEN

MEMBER
1994 FORD BRONCO
V8
4WD
AUTOMATIC
180,000 MILES

My 1994 Ford Bronco 5.8L XLT recently failed California Smog test. Dealer told me PCM needed replacement and it would cost $679 to have the PCM taken out and repaired as Ford does not make this part anymore.

they told me until the PCM is fixed they can't tell what the smog problem is although it may be a catalytic converter problem.

How do I pull the PCM out myself on this car and have it sent in for repair. I saw a few sites which do repair on these units.

Tuesday, November 16th, 2010 AT 12:43 PM

2 Replies

ERNEST CLARK

MECHANIC
1,730 POSTS

If your car is running properly, I really doubt there's anything wrong with your PCM. And your cats aren't controlled by the PCM and neither one affects the other.

I suggest you take your truck to someone you can verify is reputable.

Also, if you can get a print out from the California testing station, it should tell you why you failed the smog test. If it's an emissions devise, then that can be replaced. If your tail pipe is putting out to many HC's, CO, etc, then that can be narrowed down by a competent technician.

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Tuesday, November 16th, 2010 AT 12:47 PM

JOHN PETERSEN

MEMBER
2 POSTS

Thanks. I took the car to the Ford Dealer in Roseville who I would presume is competent but perhaps not?

The smog test report indicated very high levels of HC, CO and NO and deemed it a "gross polluter".

Dealer technician stated "139789 diagnosis for failed smog elsewhere, review VIR from failed test, EEC test codes 172 and 173 (running lean and rich), pinpoint tests found PCM shorted internally causing voltage on 02 PID with KOEO, needs PCM sent out for repair and retest for other possible causes for failure including CAT converter efficiency.

Car seems to run just fine.

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Tuesday, November 16th, 2010 AT 1:15 PM