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I am looking at buying a 1999 S80 with 31,000 miles that appears to be in very good condition. One problem though it had a check engine light and the owner said that it just came on a couple of days ago. Of course, I took it to my mechanic and he checked out the car but when he hooked it up to his computer the system showed two codes 1171 and 1181, but his software does not tell him what they mean. I would like to avoid taking it to a Volvo dealer and paying a couple hundred dollars just to find out if I should buy the car.

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P1171 = ECM-261A= Long-term fuel trim Upper limit

P1181 =ECM-271ALong-term fuel trim, bank 2 Upper limit

Diagnostic trouble code (DTC) information


The control module receives information from the heated oxygen sensor (HO2S) about the fuel / air mixture when idling at both the lower and upper part-load range. If the fuel / air mixture deviates from λ=1, the short-term fuel trim will compensate for this by adjusting the injection time so that λ=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. Diagnostic trouble code (DTC) ECM-271A will be stored when the long-term trim must be adjusted to almost maximum in the lower part load area.

Substitute value

Possible source

Upper limit:
-intake air leakage
-exhaust system air leakage
-low fuel pressure
-defective heated oxygen sensor (HO2S)

My 2001 s80 2.9l had the same thing , changed the air filter (pretty blocked) and cleaned the air mass sensor with non-chlorinated brake cleaner.

CEL (check engine light) should go off after 5 or 6 complete start and go cycles but the codes will reamain in the computer till you erase them with a scanner.

Hope it helps !

By the way this text comes from my Vadis software .

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