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P1131 Diagnostic Trouble Code Discussion for May 2011

Heated Oxygen Sensor (Bank 1 Sensor 1) Indicates A/F Ratio Too Lean

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Trouble Ticket Help Requests for DTC P1131
Help Request Posted
1998 Ford Escort SE 2.0L Excessive Emissions, MIL Lamp on VIN: 1FAFP15P4W
P1131: lack of o2 switching. Came in for 3% NOx on emmission. 1% is max. typically. Hooked up Modis and Launch. Front O2 reads 0 steady. LT and ST trim reads 0 steady. Rear O2 bouncing around. We've replaced both O2's and used PCM. Backprobed on computer connections, front 02 and rear O2 ...
May 18, 2011