Ignition System

3-1-1 VEHICLE SPEED SENSOR SIGNAL

Condition(s) for DTC
^ The ICM is dependent on this signal for fan control, timing control etc.. The DTC is recorded if the speed exceeds 3000 rpm, the load signal (Tq) corresponds to part load and the signal is absent for 5 seconds.

Substitute value
^ The control module will assume a value equivalent to approx. 4 km/h (3 mph).

Fault source(s)
^ Signal lead short-circuited to ground or supply.
^ Open-circuit in signal lead.
^ Faulty speedometer.
^ Fault in sensor circuit.

Fault symptom(s)
^ None.

TESTING PROCEDURE





Other DTCs
^ Read other DTCs.

If MFI DTC 1-2-1 is recorded:
- Proceed to: Testing By Trouble Code / Fuel Injection System / DTC 1-2-1 Mass Air Flow Sensor Signal.
If DI DTC 1-4-4 is recorded:
- Proceed to: DTC 1-4-4 Mass Air Flow Sensor (Load Signal).
If neither DTC is recorded:
- Check Status message.





Status messages
^ Check current Status Message.

If Status message is: Permanent fault, signal faulty:
- Proceed to: PERMANENT FAULT, SIGNAL FAULTY Section below.
If Status message is: Intermittent fault, signal faulty:
- Proceed to: INTERMITTENT FAULT, SIGNAL FAULTY Section below.

^ The fault counter indicates the number of starts during which the ICM has detected a fault free signal after the DTC has been recorded.

PERMANENT FAULT, SIGNAL FAULTY

Checking speedometer
^ Test drive car.
^ Check that speedometer is working.

If speedometer is not working:
- Carry out fault tracing on combined instrument and speedometer circuit.
If speedometer is working:
- Check combined instrument for DTCs.





Checking combined instrument for DTCs
^ Switch ON ignition.
^ Check if DTC 1-3-1 is recorded in combined instrument (terminal 7 on DLC A).

If DTC 1-3-1 is not recorded:
- Check VSS signal.
If DTC 1-3-1 is recorded:
- Check lead between MFI B18 and combined instrument connector terminal A:7 for short-circuit to supply.





Checking VSS signal
^ Connect test box to Ignition system and check ground terminals.
^ Plug ICM into test box adapter.
^ Move gear lever to neutral.
^ Jack up car so that front wheels are free to rotate.





^ Switch ON ignition.
^ Connect voltmeter across #48 (ICM B18) and #20 (ICM A20) on test box.
^ Spin front wheels slowly.

Instrument reading should oscillate between approx. 0.5 Volts and over 3.5 Volts.

If reading is correct:
- DTC is due to poor connection in ICM connector.
- Check connector for contact resistance and oxidation.
If instrument indicates constant value of approx. 0 Volts:
- Check lead between MFI B18 and combined instrument connector A:7 for short-circuit to ground.
If instrument indicates constant value of approx. 5 Volts:
- Check lead between MFI B18 and combined instrument connector terminal A:7 for open-circuit.

INTERMITTENT FAULT, SIGNAL FAULTY





Checking DTCs in combined instrument panel
^ Switch ON ignition.
^ Check if DTC 1-3-1 is stored in combined instrument (terminal 7 in DLC A).

If DTC 1-3-1 is recorded:
- Check lead between MFI B18 and combined instrument connector terminal A:7 for intermittent short- circuit to supply.
If DTC 1-3-1 is not recorded:
- Check combined instrument and VSS circuit for intermittent fault.
- Check ICM connector, combined instrument connector and connector 24/13 for loose connections.
- Check lead between MFI B18 and combined instrument connector terminal A:7 for intermittent open-circuit, and for intermittent short-circuit to ground.