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.

IMPORTANT: Check the crankcase ventilation for leaks before performing any other fault diagnosis.

See Inspection of crankcase ventilation hoses
DTCs P0101, P0106, P0300, P0455 and P1300 can be generated as a result of the DTCs above when the cause of the DTC is a leak in the crankcase ventilation. Once the leak has been rectified, the other DTC can be deleted.

On-Board Diagnostics

Type of diagnosis:
^ Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
^ Engine running and closed loop active. One multiplicative and one additive adaptation performed.

Fault criteria:
^ Additive adaptation exceeds 5 mg/c for more than 30 s.

Dependents:
^ P0116, P0117, P0118, P0131, P0132, P0134, P0444, P0445 and P1105.

System reaction to a fault:
^ None.

OK report:
^ Provided the fault criteria are not fulfilled during the driving cycle the OK report occurs at ignition off before the engine stalls. Two types of OK reports can be given: Type 1: If a DTC is already stored for the diagnosis and similar operating conditions have occurred (coolant temperature above or below 71 degree C, engine speed ±375 rpm and load ±10%). Type 2: If there is no DTC stored for the diagnosis or similar operating conditions have not occurred

Fault handling: (For more information, Fault Handling II, Emission-Related Misfiring or Fault In Fuel System)

^ Type II.

Diagnostic help
The engine's fuel requirement has been 5 mg/c greater during idling than the control module has calculated 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, as 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 mass is OK, then the fuel supply must be checked, i.e. pressure, pressure response, pump flow and then the injectors.

Functions in the diagnostic tool related to the fault:
^ Diagnostic status for the diagnosis.
^ O2S 1, unit V
^ Additive adaptation, unit mg/c.
^ Short term fuel trim, unit %.
^ Purge adaptation, unit %.
^ Airmass deviation from calculated, in %.

For more information refer to description of read values, Menu Read Values

P0172