Signal Too Low

Other Diagnostic Trouble Codes
- Read out OTHER DTCs in the Motronic 4.4 engine management system.
- Is Motronic 4.4 engine control module (ECM) diagnostic trouble code (DTC) EFI-411 stored?

Yes:
- Proceed to: Fault-tracing Information section below.

No:
- Proceed to: Status Message section below.

Fault-tracing Information
- Fault-trace according to engine management system diagnostic trouble code EFI-411.
- Fault corrected.





Status Message

NOTE: To get the correct status message the ignition must be switched on for approx. 15 seconds before reading the diagnostic trouble code.

- Read off diagnostic trouble code.
- Does the status indicate PERMANENT FAULT?

Yes:
- Proceed to: Checking Throttle Position Sensor Signal section below.

No:
- Proceed to: Intermittent Fault section below.





Checking Throttle Position Sensor Signal
- Ignition ON.
- Go into scrolling values.
- Read off the throttle position (TP) sensor signal.
- Press accelerator pedal (AP) to floor and check if the TP sensor signal increases.
- Does the value increase?

Yes:
- Proceed to: Checking Voltage Drop Over The Engine Control Module Signal Ground section below.

No:
- Proceed to: Checking Signal Cable Resistance To Ground section below.





Checking Signal Cable Resistance To Ground
- Ignition OFF.
- Connect test box to Motronic 4.4 engine control module.
- Engine control module disconnected.
- Disconnect the transmission control module (TCM).
- Connect an ohmmeter between test box # 20 (# B20) and ground.
- The ohmmeter should read approx. 0 Ohms.

If reading is OK:
- Proceed to: Checking Signal From Engine Control Module 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 # 7 and engine control module # B20 for a short-circuit to ground.
- Proceed to: Verification section below.





Checking Signal From Engine Control Module
- Ignition OFF.
- Connect the engine control module.
- Ignition ON.
- Connect a voltmeter between # 20 (# B20) on the test box and ground.
- The voltmeter should normally indicate approx 0.5 Volts at closed throttle position (CTP). The voltage should not drop below 0.1 Volts at closed throttle position.
- Is the reading OK?

Yes:
- Proceed to: Connecting The Test Box section below.

No:
- Proceed to: Checking Throttle Position Sensor Circuit section below.

Checking Throttle Position Sensor Circuit
- Check throttle position sensor circuit for the Motronic 4.4 engine control module, diagnostic trouble code EFI-411. Throttle position sensor signal, permanent fault, signal too low.
- Proceed to: Verification section below.





Connecting The Test Box
- Ignition OFF.
- Connect test box to the transmission control module and check ground points.
- Proceed to: Checking Signal To The Transmission Control Module section below.





Checking Signal To The Transmission Control Module
- Ignition OFF.
- Connect the test box to the automatic transmission control module.
- Engine control module connected.
- Ignition ON.
- Connect a voltmeter between # 7 and # 15 on the test box.
- The voltmeter should normally read approx 0.5 Volts at closed throttle position. The voltage should not drop below 0.1 Volts at closed throttle position.
- Is the reading OK?

If reading is OK:
- Proceed to: Checking For Contact Resistance And Oxidation section below.

If reading is incorrect:
- Proceed to: Checking For An Open-circuit section below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- The diagnostic trouble code was caused by loose connections in the control module connectors. Check control module connectors for contact resistance and oxidation and remedy.
- Proceed to: Verification section below.





Checking For An Open-circuit
- Check cable between automatic transmission control module # 20 and engine control module # B20 for an open-circuit.
- Proceed to: Verification section below.





Checking Voltage Drop Over The Engine Control Module Signal Ground
- Ignition OFF.
- Connect test box to Motronic 4.4 engine control module.
- Engine control module connected.
- Ignition ON.
- Turn on as many power consuming items as possible.
- Connect a voltmeter between # 42 (# A42) on the test box and ground terminal 31/53. Note the voltmeter reading.
- Proceed to: Connecting The Test Box section below.





Connecting The Test Box
- Ignition OFF.
- Disconnect the test box from the engine control module.
- Connect test box to the transmission control module.
- Proceed to: Checking Voltage Drop Over The Transmission Control Module Signal Ground section below.





Checking Voltage Drop Over The Transmission Control Module Signal Ground
- Ignition OFF.
- Connect the control modules.
- Ignition ON.
- Turn on as many power consuming items as possible.
- Connect a voltmeter between # 1 on the test box and ground terminal 31/53. Note the reading. Add the previous reading to the new reading.
- When added together the sum of the two readings should not be more than 0.1 Volts.

It reading is OK:
- Proceed to: Checking Voltage Drop Over Signal Ground And Power Ground section below.

If reading is incorrect:
- Proceed to: Checking For Contact Resistance And Oxidation section below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- Check ground terminal 31/53 and transmission control module connectors for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking Voltage Drop Over Signal Ground And Power Ground
- Ignition ON.
- Turn on as many power consuming items as possible. Connect a voltmeter between # 7 and # 15 on the test box.
- The voltmeter should read less than 0.6 Volts.

If reading is OK:
- Proceed to: Checking Throttle Position Sensor Signal From Engine Control Module section below.

If reading is incorrect:
- Proceed to: Checking For Contact Resistance And Oxidation section below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- Check ground terminals 31/53 and 31/66, the cables between the ground terminals and transmission control module # 1 and # A15, and the transmission control module connector for contact resistance and oxidation.
- Proceed to: Verification section below.





Checking Throttle Position Sensor Signal From Engine Control Module
- Ignition ON.
- Connect a voltmeter between # 7 and # 15 on the test box.
- The voltmeter should normally read approx 0.5 Volts at closed throttle position. The voltage should not drop below 0.1 Volts at closed throttle position.
- Is the reading OK?

If reading is OK:
- Proceed to: Checking For Contact Resistance And Oxidation section below.

If reading is incorrect:
- Proceed to: Checking Throttle Position Sensor Circuit section below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- The diagnostic trouble code was caused by loose connections in the control module connectors. Check control module connectors for contact resistance and oxidation and remedy.
- Proceed to: Verification section below.

Checking Throttle Position Sensor Circuit
- Check throttle position sensor circuit for the Motronic 4.4 engine control module, diagnostic trouble code EFI-411. Throttle position sensor signal, permanent fault, signal too low.
- Proceed to: Verification section below.





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

- Ignition OFF.
- Wait approx. 10 seconds.
- Ignition ON.
- Wait approx. 15 seconds.

- Read off the status of the Diagnostic trouble code. Does the status indicate INTERMITTENT FAULT?

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: Other Diagnostic Trouble Codes section above.





Intermittent Fault
- Ignition OFF.
- Check connectors on the transmission control module and on the engine control module for loose connections, contact resistance and oxidation.
- Check the cable between transmission control module # 7 and engine control module # B20 for an intermittent open-circuit and intermittent short-circuit to ground.
- Check ground terminals 31/53 and 31/66 for contact resistance and oxidation.
- Check throttle position sensor circuit for Motronic 4.4 engine control module, diagnostic trouble code EFI-411 Throttle position sensor signal, permanent fault signal too low.
- 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: Other Diagnostic Trouble Codes section above.

No:
- Operation done.