Originally posted by projectSHO89:
Originally posted by Rogerm60:
(551) The 95 has no way to know wether the IMRC is open or closed.



Correct, however... It can tell if the PCM's driver circuit is behaving correctly as it would if the IMRC were working properly. There is no feedback sensing beyond that since there is no sensor directly on that solenoid.

The PCM has an internal sensing capability on the line that controls the IMRC solenoid. The output pin of the PCM would normally be at Vbatt when the solenoid is not energized. To energize it, the PCM "grounds" that pin, allowing current flow through the solenoid and actuating it.

If the internal monitor circuit does not see this transition from Vbatt to ground when it is expected, it will cause the PCM to report the 551 error.

Possible causes: Loss of Vbatt to IMRC solenoid, open solenoid, open connection between the solenoid and the PCM output pin, internal PCM failure (driver circuit), or internal PCM failure (sensing circuit).

Check and make sure the IMRC solenoid is not unpluuged is the simples check.

Steve



First, this would all be fine and great except ONLY the 95's (which I notice you've got a 98) use a vaccum controlled IMRC. So Roger was right by saying that.

Second,
Originally posted by nOsSvTcOnToUr:
(332)Insufficient EGR flow detected(EGRP,EVP,PFE,DPFE)

(551) IDLE air Control (IAC) cicuit failure KOEO

Second for code 332 check and see if the egr holds vaccum, if it does mostly likely its your DPFE sensor

For code 551 mostly like you will need to replace your IAC sensor. Good luck and hope that helps


This is right per Chiltons manual. I'm not sure where the dalidesign site got their info but it's wrong. Also, you can sometimes get by with simply cleaning the IAC w/ brake cleaner. As for the DPFE sensor, it's located on the rear of the engine, underneath the right (rear) head. It's a rectangle box about 3.5"Wx2"Hx3/4"D. It has two vaccum lines coming off of the EGR tube coming from the rear manifold and plug into the bottome of the sensor. It also has a 3 wire harness connected to it on the rear (driver's side). The dealer told me they replace a ton of them so it MIGHT be.

It could also be, if you pull the throttle body off, there are 3 ports (4,5 and 6 o'clock position) for the EGR return into the UIM. These ports get plugged w/ carbor and don't allow EGR return. Replace the TB gasket if you do remove it. This was my problem when I got code 332. I didn't know about those 3 ports and ended up spending around $300 replacing DPFE, EGR and several other parts when all it would have cost me was a damn $3 TB gasket fix it.

Hope this helps,
Dale

I'll put holes in him!!