CI-221 Vehicle Speed Signal

Condition:

Speedometer:

- The combined instrument panel registers no vehicle speed signal (input signal) when the engine speed (RPM) signal exceeds 1,500 rpm for at least a minute while engine coolant temperature (ECT) is above 50°C (122°F).

Possible Source:
- Open-circuit in signal cable.
- Large contact resistance.
- Fault in ABS system.
- High idling speed, > 1,500 rpm.
- Short-circuit to ground in signal cable.
- Short-circuit to supply voltage in the signal cable.

Fault Symptom(s):
- Speedometer reading too small or no reading.
- Diagnostic trouble code (DTC) is stored in engine management system.
- In cars with ECC blower fan speed does not drop with increasing speed.
- In cars equipped with a trip computer, incorrect values for average speed, average fuel consumption, actual fuel consumption and trip computer trip odometer are displayed.
- Cruise control stops working and a diagnostic trouble code (DTC) is stored.

Start fault-tracing with step 1, below.

1) Checking other Diagnostic Trouble Codes (DTCs):

Ignition On:

- Ignition on.





- Read off diagnostic trouble codes (DTCs) in the ABS system.
- Are diagnostic trouble codes (DTCs) ABS - 311 and ABS - 312 stored?

Yes: Go to step 2, below.
No: Go to step 3, below.

2) Diagnostic Trouble Codes (DTCs) ABS - 311 and ABS - 312 Stored:
- Fault-trace according to appropriate ALLDATA section for Brakes, Traction Control and Anti-Lock Braking system.

3) Status Check:

Engine Running:

- Start engine.





- Test drive the car at speeds above 20 km/h (12 mph), or lift up the front suspension and remove both front wheels.

WARNING: Test drive cars with AWD at a speed above 20 km/h (12 mph), or lift up the front and rear suspension and remove all wheels.

NOTE:
- When the rear wheels are stationary and the front wheels rotate, diagnostic trouble codes (DTCs) may be stored in the ABS system. Erase any diagnostic trouble codes (DTCs) stored in the ABS system after fault-tracing.
- Ensure that the front wheels are not rotating when the gear selector is moved.

- Go into scrolling values.





- Read off speed.
- Is the speed displayed within its permitted range?

Yes: Go to step 12, below.
No: Go to step 4, below.

4) Checking Engine Idling Speed:

Engine Running:

- Engine idling.
- Go into scrolling values.





- Read off engine speed (RPM).
- Is idling speed over 1,500 rpm?

Yes: Go to step 5, below.
No: Go to step 6, below.

5) Adjusting Engine Idling Speed:
- Check and remedy idling speed according to the the appropriate ALLDATA section for the relevant fuel injection system.

6) Checking ABS Signal:
- Ignition off.





- Connect breakout box to ABS control module and check ground terminals according to Appropriate ALLDATA section for brakes, Traction Control and Anti-Lock braking System.





- Disconnect ABS control module.

Ignition On:

- Ignition on.





- Connect a voltmeter between # 6 and # 8 on the breakout box.
- The voltmeter should read approx. 6 V.

If reading is OK, go to step 9, below.
If value is lower, go to step 7, below.
If value is higher, go to step 8, below.

7) Checking for an Open-Circuit or Short-Circuit to Ground:





- Check cable between combined instrument panel # A3 and ABS control module # 6 for an open-circuit and a short-circuit to ground. Permanent Fault
- Then Continue with step 10, below.

8) Checking for a Short-Circuit to Supply Voltage:
- Check cable between combined instrument panel # A3 and ABS control module # 6 for a short-circuit to supply voltage. Permanent Fault
- Then continue with step 10, below.

9) Fault Cause and Checking for Contact Resistance and Oxidation:
- The cause of the diagnostic trouble code (DTC) has been loose connections in the ABS control module connector. Check connector for contact resistance and oxidation. Permanent Fault
- Then continue with step 10, below.

10) Verification:

Note: After carrying out the repair check that the fault has been remedied.

- Ignition off.

Connect Connector:

- Reconnect connectors, reinstall components.

Engine Running:

- Start engine.





- Test drive the car at speeds above 20 km/h (12 mph), or lift up the front suspension and remove both front wheels.

WARNING: Test drive cars with AWD at a speed above 20 km/h (12 mph), or lift up the front and rear suspension and remove all wheels.

NOTE:
- When the rear wheels are stationary and the front wheels rotate, diagnostic trouble codes (DTCs) may be stored in the ABS system. Erase any diagnostic trouble codes (DTCs) stored in the ABS system after fault-tracing.
- Ensure that the front wheels are not rotating when the gear selector is moved.

- Go into scrolling values.





- Read off speed.
- Is the speed displayed within its permitted range?

Yes: The fault is corrected.
No: Go to step 11, below.

11) Fault-Tracing Information:
- The verification result shows that the fault persists.
- Do you want to exit fault-tracing?

Yes: The fault is not corrected!
No: Go back and start over at step 2, above.

12) Faulty signal, Intermittent Fault:
- The cause of the diagnostic trouble code (DTC) may have been that the engine speed (RPM) has been over 1,500 rpm for at least a minute with the gear selector in neutral.
- Then continue with step 13, below.

13) Checking Cables and Terminals:





- Check combined instrument panel connector A and ABS control module connector for loose connections, contact resistance and oxidation. Also, check cable between combined instrument panel # A3 and ABS control module # 6 for an intermittent open-circuit.
- Then continue with step 14, below.

14) Fault-Tracing Information:
- For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.
- If you want to repeat fault-tracing, start over at step 1, above.