Lambda Control stuck at 1.00
04-07-2008, 04:13 PM
#1
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Lambda Control stuck at 1.00
Heater circuit works, all wires to ECU connector show continuity, O2 sensor is brand new and sweeps on my narrow band A/F meter. Any thoughts? Bad ECU? Could a bad MAF cause the same? 1995 Audi S6 AAN motor.
04-11-2008, 04:08 PM
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Bentley says it is a problem and the car won't pass emissions.
According to the Bentley manual, the lambda control should fluctuate between .96 and 1.04. It says it should not remain at 1.00. It remains there for at least 10 minutes. I have never checked longer than that but Bentley says it should start fluctuating within 1.5 minutes. Car warms up fine and VAGCOM reads the coolant temp sensor as being correct.
04-13-2008, 07:29 AM
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Right.
But 1.00 (in this case) means the ECU has stayed in open loop. It is finding an implausible signal somewhere and ignoring it and refusing to go into open loop. The ECU knows something is wrong somewhere and presumably reverting to the fuel maps or stored settings it remembers from before. I need to figure out why it won't go closed loop. Unfortunately, the information through VAGCOM is not as complete as in the OBD-II systems so it's harder to figure out.
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