'92 960 Wagon Idle too Rich

[golfdub]

'92 960 wagon; Code 5-1-2 , believed to mean short term fuel mix too rich at idle. What's the fix? Thanks.

[billofdurham]

Welcome to Matthew's Volvo Site.

5-1-2 indicates that the heated oxygen sensor (HO2S) has detected a deviation in the short term fuel trim and has adjusted the injection period. If the short term fuel trim remains lean for more than 3 minutes and the engine temperature exceeds 75C the code is set.

There are two possible sources for the code:
Faulty sensor signal.
High fuel pressure.

Try clearing the code and see if it returns. There may have been a momentary glitch which caused this and it may not repeat itself.

Bill.

[golfdub]

Thanks for the prompt reply. Cleared the codes, ran the engine, still shows 5-1-2. What next?