DTC 5-1-2 Short Term Fuel Trim, Lower Limit

5-1-2 SHORT TERM FUEL TRIM (INTEGRATOR), LOWER LIMIT

Condition(s) for DTC
^ The short term fuel trim value is a measure of degree to which the injection period in the basic MFI module program must be varied to ensure that the engine is supplied with the optimum air/fuel mixture. This optimum mixture corresponds to a value of Lambda = 1. If the engine is running rich, the short term fuel trim will reduce the injection period to restore the optimum mixture. A DTC will be recorded if the engine runs so rich that the short term fuel trim reaches its lower limit and remains there for 166 seconds.

Substitute value
^ None.

Fault source(s)
^ Heated Oxygen Sensor (HO2S) signal lead short-circuited to ground.
^ HO2S faulty.
^ Contact resistance and oxidation in Mass Air Flow (MAF) sensor connector.
^ MAP sensor faulty.

Fault symptom(s)
^ Fault may cause high fuel consumption and driving problems.