Hi All,

Have an S90 that displayed PNP failure (flashing arrow and blinking WES switch).

I rowed the shifter back and forth to clean up the PNP points, and reset the code. Success! The flashing lights were gone -Or so I thought.

The CEL light comes on approximately 5 seconds after the engine starting, yet there is no code associated with it?

Does anyone have any idea what this could be?

Thanks!
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-- 1998 S90 222k -- | -- 1998 S90 83k--

You did check for a new code, right??
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Will I buy another Volvo??? We'll see....

Yes, I drove to autozone with the CEL lit and nothing. No code to speak of! Is there anyway beyond unplugging the battery to reset the code?

Dear jlvolvo,

Hope you're well. You're right! Disconnect negative battery cable from the negative battery terminal. Wait 15 minutes. Then re-connect. I'll bet the code "goes away".

Hope this helps.

Yours faithfully,

Spook

I left the negative terminal off all night! I am worried it is the transmission throwing a code a simple OBDII reader can not decipher.

OBD II should give you the correct tranny code if there actually is one. Years back I had a similar issue with my 93 850. Just to be sure everything is okay, you checked the tranny fluid level and fluid condition?

After leaving the battery disconnected all night did the CEL return?
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Will I buy another Volvo??? We'll see....

Yes the CEL came back after all night disconnect. Same drill, after the engine's been running for ~5 seconds the CEL illuminates.

I haven't checked the fluid levels; Are you suggesting that the transmission could throw a CEL with no code because of a fluid issue?
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-- 1998 S90 222k -- | -- 1998 S90 83k--

No, I’m not saying that a low fluid level would directly cause a CEL. However, it could indirectly cause a CEL because an excessive heat issue (fluid related) might affect a tranny component causing a code to be thrown.

Your car, like my former 850’s, have a read out for specific tranny codes.

Have you tried to scan for codes today? Is there still no code?

If still no code, you could try cleaning the PNP again and disconnecting the battery. Sometimes CEL’s are difficult to clear.
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Will I buy another Volvo??? We'll see....

Oh okay, I see what you're saying.

Haven't scanned for code today, I really ought to buy my own OBDII reader...

I found this thread about a 960 displaying similar behavior but no one ever reported back if it was fixed: https://volvoforums.com/forum/volvo-260-760-960-28/96-960-check-engine-light-no-codes-88487/

One commenter suggests it is a short in the system ( I am skeptical of this ).

Another says it is simply a faulty PNP ( More believable, as this blank CEL seems to coincide with PNP breaking ).

I didn't think this CEL could be the PNP as they usually display a very identifiable error sequence with multiple flashing lights (as we all know), but I suppose my only option is to replace the PNP and see if that resolves the issue!


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-- 1998 S90 222k -- | -- 1998 S90 83k--

Before replacing the PNP, try cleaning the PNP/rowing the shifter and disconnecting the battery again. Sometimes the CEL’s are difficult to clear and take multiple attempts. Moral of the story - keep trying!!
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Will I buy another Volvo??? We'll see....

Dear jlvolvo,

Hope you're well. The return of the CEL after a power-down suggests there is a problem. On 940s - insights into which may have no relevance to an S/V 90 - a "Check Engine Light" (CEL) usually indicates a problem with a pollution control component.

Thus, I'm puzzled as to the absence of a code indicating, for example, that an oxygen sensor's signal is missing. If memory serves, there are two oxygen sensors on an S/V 90.

Hope this helps.

Yours faithfully,

Spook