Faulty Signal.

Faulty signal.

Status check

Note! If the diagnostic trouble code (DTC) for the engine coolant temperature (ECT) sensor is stored in the fuel/ignition system start fault-tracing according to the diagnostic trouble code (DTC) first because it will probably solve the fault,

- Ignition on.
- Go into scrolling values.
Read off engine coolant temperature (ECT).

Does the engine coolant temperature (ECT) display -40 °C?

Yes - Fault-tracing information

No - Faulty signal. Intermittent fault

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Fault-tracing information
Fault-trace for the relevant fuel/ignition system.

Continue - Verification

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Information

Fault-tracing information
Continued fault tracing depends on the vehicle's engine control module.

Select a control module.

Fenix 5.2 - Breakout box connection

Motronic 4.3 - Breakout box connection

Motronic 4.4 - Breakout box connection

MSA 15.7 - Breakout box connection

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Breakout box connection

Connection to connector B
951 1351 ADAPTOR 86-PIN 951 1351 Adaptor 86-Pin 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428
Connecting up the Test box to Fenix 5.2

Is the test box connected to the control module?

Yes - FAULT FOUND

No -

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Connecting test box to connector B (grey)

- Ignition off.
- Disconnect control module.
- Connect adapter 951 1351 ADAPTOR 86-PIN 951 1351 Adaptor 86-Pin to control module connector.
- Connect test box 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to adapter, connector B.

Press Continue.

Continue -

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Checking ground point #B28

- Ignition off.
- Switch off anything which might drain the battery, such as courtesy lights and radio.
- Connect control module.

- Using an ohmmeter, take reading between #B28 and battery negative terminal.

Ohmmeter should read approx. 0 ohms.

OK - Go back to fault tracing where you left off.
No Fault Found

Not OK - Check ground points at rear of engine and leads to them for open circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance and oxidation as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

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Checking for open-circuit, contact resistance and oxidation

- Check ground points at rear of engine and leads to them for open circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance and oxidation as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Press Continue when fault is repaired.

Continue -

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Verification

Hint: After repair, it is necessary to check that the fault has been corrected.
Perform as described below.

- Ignition off.
- Reconnect connectors, components etc.
- Switch off anything which might drain the battery, such as courtesy lights and radio.
- Connect control module.

- Using an ohmmeter, take reading between #B28 and battery negative terminal.

Ohmmeter should read approx. 0 ohms.

OK - FAULT FOUND

Not OK -

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Troubleshooting Information

Information

Fault-tracing information
The fault should be diagnosed and remedied. Since this is not the case the fault-tracing process has failed.
Complete the fault-tracing for those fault or try again.

Do you want to terminate fault-tracing at this time?

Yes - Exit fault-tracing

No - Attempt New Test

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Attempt New Test -

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No Fault Found - No Fault Found

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Breakout box connection

Connector B
951 1351 ADAPTOR 86-PIN 951 1351 Adaptor 86-Pin 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428
Connecting up the Test box to Motronic 4.3

Is the test box connected to the control module?

Yes - FAULT FOUND

No -

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Connection of break-out box to connector B (grey)

- Switch off ignition.
- Disconnect ECM.

Note! The ECM must not be removed from the car until the main relay has interrupted the supply. This may take up to 150 seconds after the ignition has been switched off.

- Plug adapter 951 1351 ADAPTOR 86-PIN 951 1351 Adaptor 86-Pin into ECM base and connect break-out box 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to adapter.

Press Continue.

Continue -

Continue - Resume fault tracing at point of interruption.

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Checking ground terminal #B28

- Switch off ignition.
- Switch off all power consumers, such as interior lighting and radio.
- Reconnect ECM.

- Use ohmmeter to measure resistance between #28 (#B28) on break-out box and battery negative terminal.

Instrument should indicate approx. 0 ohms.

OK - Resume fault tracing at point of interruption.
No Fault Found

Not OK - Check ground terminals 31/32 and 31/33 at rear of engine and associated wiring for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , and for contact resistance and oxidation as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

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Checking for open-circuit, contact resistance and oxidation

- Check ground terminals 31/32 and 31/33 at rear of engine and associated wiring for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , and for contact resistance and oxidation as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

- Switch off ignition.
- Switch off all power consumers, such as interior lighting and radio.
- ECM connected.

- Use ohmmeter to measure resistance between #28 (#B28) on break-out box and battery negative terminal.

Instrument should indicate approx. 0 ohms.

OK - FAULT FOUND

Not OK -

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Troubleshooting Information
Information
Attempt New Test -

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No Fault Found - No Fault Found

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Breakout box connection
Connector B

No Fault Found - No Fault Found

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Breakout box connection

No Fault Found - No Fault Found

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Checking engine coolant temperature (ECT) sensor signal

- Ignition off.
- Disconnect the engine control module (ECM).
- Ignition on.
Connect a voltmeter to the breakout box as follows: #23 (#B23) and #28 (#B28)

The voltmeter should read approximately 6 V.

OK - Checking for contact resistance and oxidation

Low - Checking for an open-circuit and short-circuit to ground

High - Checking for a short-circuit to supply voltage

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Checking for an open-circuit and short-circuit to ground
Check cable between combined instrument panel #A26 and engine control module (ECM) #B23.
On cars with ECC: Check cable between combined instrument panel #A26 and ECC control module #C2 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Checking for a short-circuit to supply voltage
Check cable between combined instrument panel #A26 and engine control module (ECM) #B23.
On cars with ECC: Check cable between combined instrument panel #A26 and ECC control module #C2 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Then select continue.

Continue - Verification

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Checking for contact resistance and oxidation
The cause of the diagnostic trouble code (DTC) has been loose connections in the engine control module (ECM) connector. Check connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Then select continue.

Continue - Verification

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Verification

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

- Ignition off.
- Reinstall connectors, components etc.
- Ignition on.
- Go into scrolling values.
Read off engine coolant temperature (ECT).

Does the engine coolant temperature (ECT) display 40°C?

Yes - FAULT FOUND

No - info1 No Fault Found

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Fault-tracing information

Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit fault-tracing

No - Attempt New Test

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Faulty signal. Intermittent fault

Faulty signal. Intermittent fault

Checking component
Check combined instrument panel connector A and engine control module (ECM) connector for loose connections according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Check cable between combined instrument panel #A26 and engine control module (ECM) #C2 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
On cars with ECC: Check cable between combined instrument panel #A26 and ECC control module #C2 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.

Continue - DONE

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Fault-tracing information

Information

Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).

Do you want to view the information again?

Yes - Attempt New Test

No - FAULT FOUND

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