Fault Conditions

P1181
Long Term Fuel Trim Additive. Max Value, Air/Fuel too Lean.

Fault symptoms
- CHECK ENGINE.
- The engine may stop after starting, run unevenly and misfire, or idle speed too fast.

On-Board Diagnostics
Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and does not restart until next driving cycle.

Enable conditions:
- Engine running and closed loop active. One multiplicative and one additive adaptation have been performed.

Fault criteria:
- Additive adaptation exceeding 3.33 mg/c for more than 30 S.

Dependents:
- P0116, P0117, P0118, P0131, P0132, P0134, P0444 and P0445.

System reaction to a fault:
- None.

OK report:
- Provided that fault criteria have not been fulfilled during the driving cycle, an OK report will be given when the ignition is turned off and before the engine has stopped. Two types of OK report can be given: Type 1: If a diagnostic trouble code is already stored for the diagnosis and the same operating conditions have arisen (engine coolant temperature over or under 71°C, engine speed 375 rpm and load 10%). Type 2: If there are no diagnostic trouble codes stored for the diagnosis or the same operating condition have not arisen.

Fault handling: See "Fault diagnosis, general" for more information.
- Type II.

Diagnostic help
At idling speed, the engine fuel requirement has been 25% greater than calculated by the control module using information from the mass air flow sensor.

Fault diagnosis first determines whether the pressure sensors show about the same value with the ignition ON, since the mass air flow sensor is later compared with the intake air pressure. If the pressure sensors are OK but the mass air flow sensor is incorrect then check for air leaks after the throttle and thereafter, change the mass air flow sensor.

If the air quantity is OK, then the fuel supply is checked, i.e. pressure, response, pump flow and finally the injector functions in the diagnostic tool related to the fault:
- Diagnostic status for the diagnosis.
- 02S 1, unit V
- Additive Adaptation, unit mg/c.
- Closed loop, unit %.
- Purge Adaptation, unit %.
- Air mass deviation from calculated, unit %.

See also the description of readings in "Fault diagnosis, general" for more information.

Proceed to Diagnostic Procedures Checking the Manifold Absolute Pressure Sensor