Faulty Signal

Checking Load Signal
- Start the engine.
- Go into scrolling values.
- Read load signal.
- Normal range idling with warm engine, N position and A/C off: approx. 35 micro sec. This value increases with load.

Yes:
- Proceed to: Intermittent Fault section below.

No:
- Proceed to: Connecting The Test Box. Checking Ground Terminals section below.

Connecting The Test Box. Checking Ground Terminals
- Ignition OFF.
- Connect the test box and check ground terminals.
- Proceed to: Checking Signal Cable For Short-circuit To Supply Voltage section below.





Checking Signal Cable For Short-circuit To Supply Voltage
- Ignition OFF.
- Transmission control module (TCM) connected.
- Ignition ON.
- Connect an electrician's screwdriver (bulb at least 3 W) between # 23 and # 15 on the test box.
- The electricians screwdriver should not light.

If reading is OK:
- Proceed to: Checking Signal Cable Resistance To Ground section below.

If reading is incorrect:
- Proceed to: Checking For A Short-circuit section below.





Checking For A Short-circuit
- Check cable between transmission control module # 23 and engine control module (ECM) # B12 for a short-circuit to supply voltage.
- Proceed to: Verification section below.





Checking Signal Cable Resistance To Ground
- Ignition OFF.
- Engine control module disconnected.
- Disconnect the transmission control module.
- Connect an ohmmeter between # 23 and # 15 on test box.
- Does the ohmmeter read infinite resistance?

Yes:
- Proceed to: Checking Signal Cable section below.

No:
- Proceed to: Checking For A Short-circuit section below.





Checking For A Short-circuit
- Check cable between # 23 transmission control module and engine control module # B12 for a short-circuit to ground.
- Proceed to: Verification section below.





Checking Signal Cable
- Ignition OFF.
- Connect the transmission control module.
- Connect the engine control module.
- Start the engine.
- Go into SCROLLING VALUES.
- Read load signal.
- Normal value at idling speed with engine warm, N position and A/C off is approx. 35 micro sec. This value increases with load.
- Does value increase with engine load?

Yes:
- Proceed to: Checking For A Short-circuit section below.

No:
- Proceed to: Checking For An Open-circuit section below.





Checking For A Short-circuit
- The diagnostic trouble code (DTC) was caused by loose connections in the transmission control module connector.
- Remedy short-circuit to ground in transmission control module.
- Proceed to: Verification section below.





Checking For An Open-circuit
- Check cable between transmission control module # 23 and engine control module # B12 for an open-circuit.
- Proceed to: Verification section below.





Verification
- After repairs have been completed they must be verified as follows to ensure that the fault has been eliminated:

- Ignition OFF.
- Reconnect the connectors, reinstall components etc.
- Ignition ON.
- Go into scrolling values.
- Read load signal.
- Engine idling.

- Normal range idling with warm engine, N position and A/C OFF: approx. 35 micro sec. The value increases with engine load.

Yes:
- Fault corrected.

No:
- Proceed to: Fault-tracing Information section below.

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
- Fault not corrected.

No:
- Proceed to: Checking Load Signal section above.





Intermittent Fault
- Check transmission and engine control module connectors for contact resistance and oxidation.
- Check the cable between transmission control module # 23 and engine control module # B12 for an intermittent open-circuit and an intermittent short-circuit to supply voltage.
- Proceed to: Fault-tracing Information section below.

Fault-tracing Information
For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.

- Do you want to repeat fault-tracing?

Yes:
- Proceed to: Checking Load Signal section above.

No:
- Operation done.