SAAB WIS ONLINE

P1392

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE. Running unevenly and misfiring.

P1392


Cylinder 2 Misfire Detected. Catalyst Damaging. Fuel Level Low.


Fault symptoms


CHECK ENGINE.

Running unevenly and misfiring.


On-Board Diagnostics

Type of diagnosis:


- Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.


Enable criteria:


- General conditions for this trouble code: Atmospheric pressure must exceed 78 kPa and the engine coolant and intake air temperatures must exceed 7°C.

- Engine started. Fuel level below 4 litres. Main relay voltage exceeding 10V. Ignition discharge module combustion signals registered. The number of missing combustion signals is accumulated for each cylinder during 200 engine revolutions. The total number of accepted misfires during 200 engine revolutions is specified in a load and engine speed-dependent matrix.


Fault criteria:


- Number of missing combustions exceeding number of accepted misfires.


Dependents:


- P1312 and P1334.


System reaction to a fault:


- Under high engine loads, closed loop will be blocked while misfiring occurs.


OK report:


- Provided that the fault criteria have not been fulfilled during the driving cycle, an OK report will be generated when the ignition is turned off and before the engine stops. 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 above or below 71°C, engine speed ±375 rpm and load ±10%). Type 2: If a diagnostic trouble code is not already stored for the diagnosis or the same operating conditions have not arisen.


Fault handling: (See “Fault diagnosis, general” for more information.)


- Type I.


Diagnostic help

If any other trouble codes have been generated, check whether fault diagnosis should start with them. Drive the car in the load and engine speed range shown by Freeze Frame. If the engine does not misfire, the trouble code was probably due to the fuel level being too low. Drive the car so that the catalyst diagnosis is performed. If necessary, change the catalytic converter.

If the engine misfires during test driving, conduct a general inspection of connectors and hoses, and then a thorough check of compression, ignition and fuel system.

Functions in the diagnostic tool related to the fault:


Diagnostic status for the diagnosis.

Misfire counter for the relevant cylinder.

Activating misfire counter reset.

Activating ignition trigger for relevant cylinder.

Activating injector test for relevant cylinder.


See also the description of activations under ”Fault diagnosis, general” for more information.

Checking the wiring

Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.

See .