[s-cars] Re: Coolant temperature sensor fault causing low boost

[Jonas Majauskas]

On Sun, 11 Jul 2004, Phil and Judy Rose wrote:

> At 10:02 PM -0400 7/10/04, TM wrote:
> >I've recently had a problem with low boost and poor
> >boost ramp-up, seeing only 10psi constant after a long
> >time of WOT. Just after observing this problem intermittently
> >a few times, I had a radiator neck failure, so I wasn't sure
> >if the two events were connected.
> >
> >Now following the radiator replacement, I've found that I still
> >have a low boost problem after the engine is hot- pulled codes
> >and found coolant temperature sensor, intermittent fault.
> >
> >Doing the Bentley diagnostic, it seems like the multifunction temp
> >sensor is fine, this doesn't really make sense.
>
>
> I'm not sure what the Bentley "diagnostic" is. My own diagnostic
> procedure is simple: pull the connector off the MFTS. If that cures
> your low boost problem, replace the MFTS.
>

ECU error code (using blink codes) 2312 means the real coolant temperature
sensor on the back of engine block. Brett already described the procedure.

I believe MFTS failure should give "engine overheat" or similar error, not
the "coolant temperature sensor".

I got this 2312 code a few days ago (along with hard engine start).
Checked resistance between pin 30 and pin 45 in the ECU plug - no
resistance (open circuit). Checked the sensor on the engine block - 600
ohms (depends on engine temperature). Closer look to connector revealed
the source of problem - the plastic inside connector was cracked.
Maybe there is too hot for plastic to last more than 14 years :)
Replaced the connector, and voila! Check engine light now blinks out
4444, or "no fault codes stored".