WS2 FLASH CODES

Modern Ecu is capable to provide self-diagnostics. It records and stores faults in form of codes in the memory. To obtain this information a serviceman can read these codes from the instrumental panel via flashing light. Mainly this is check engine light. However, the procedure can differ depending on manufacturer and engine type. Always read the manual before starting this test.

Code number	System affected	Condition described
41	TPS	Throttle position sensor circuit
31	MAP	Vacuum sensor circuit
24	IATC	Intake air temperature circuit

The shortest way to find a fault during visual inspection is to start from the sensor or actuator which is mentioned in trouble codes table. But it doesn’t mean that this device is necessarily faulty. There is high possibility that connectors, wires, or bad earth can be suspected.

In our case connector of TPS was disconnected, and others were loose or disconnected as well. After visual inspection these connectors were re-connected and were re-checked by slight wobbling. Once we were sure in proper connection, the next stage was taken.

To clear codes we disconnected the battery for a while. Although it works well for 4A-FE engine, in other systems scanner must be used for this purpose.  

The were no codes registered afterwards.

Wrong reading from TPS always affects engine performance, brings some hesitations flat spots in its response and , as a result, bad emission.

Faulty MAP sensor or its circuit brings misunderstanding of the engine load for the ECU. Consequences are richer mixture, misfire, black smog from the exhaust pipe.

IATC sensor circuit influences onto the proportion of air fuel mixture. Depending on the situation the mixture is getting either richer or leaner than it is needed. If the ECU reads that air is cold, rich mixture can lead to the higher consumption, emission problems or even misfire. If the ECU get  reading that engine is hot while it’s cold it will be hard or some times impossible to start it.

The method  of fault localising can include volt drop test, in some cases continuity test is applicable. Once the multimeter reading doesn’t satisfy information demanding for the fault finding, the oscilloscope will be the best tool to read patterns and analyse what is out of spec with the signal.

Code number	System affected	Condition described
41	TPS	Throttle position sensor circuit
31	MAP	Vacuum sensor circuit
24	IATC	Intake air temperature circuit