Fuel Injection System

3-1-1 VEHICLE SPEED SENSOR SIGNAL

Condition(s) for DTC
^ The MFI module is dependent on this signal for idling control, fuel cut-off etc., The DTC will be recorded if the signal is absent for 5 seconds while the engine speed is over 3000 rpm and the load signal corresponds to part load.

Substitute value
^ None.

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)
^ No fuel cut-off.

TESTING PROCEDURE





Other DTCs
^ Read other DTCs.

If MFI DTC 1-2-1 is recorded:
- Proceed to DTC 1-2-1 Mass Air Flow Sensor Signal.
If MFI DTC 1-2-1 is not recorded:
- Check Status message.





Status message
^ 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.

PERMANENT FAULT, SIGNAL FAULTY





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

If speedometer is not operating:
- Carry out fault tracing on combined instrument and VSS circuit.
If speedometer is indicating correctly:
- Check DTCs in combined instrument.

Checking DTCs in combined instrument
^ 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 MFI system and check ground terminals.
^ Plug MFI module into test box adapter.
^ Place gear lever in NEUTRAL.
^ Jack up car and support securely so that front wheels are free to rotate.





^ Switch ON ignition.
^ Connect voltmeter across #48 (MFI B18) and #20 (MFI A20) on test box.





^ Spin front wheels slowly by hand.

Instrument reading should oscillate between approx. 0.5 Volts and over 5 Volts.

If reading is correct:
- DTC is due to poor connection in MFI module 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
^ Switch ON ignition.
^ Check if DTC 1-3-1 is stored in combined instrument (terminal 7 on 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 MFI module 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.