Signal Too High

SPECIAL TOOLS
Test box tool No. 981 3190, or equivalent
Volvo scan tool No. 998 8686, or equivalent

SIGNAL TOO HIGH
1. Other Diagnostic Trouble Codes (DTCs).
- Read off OTHER DTCs in the engine management system (Fenix 5.2, LH 3.2, Motronic 4.3 or Motronic 4.4).
- Are any of the these DTCs stored
EFI-243 for Fenix 5.2,
EFI-411 for LH 3.2,
EFI-411 for Motronic 4.3
EFI-411 for Motronic 4.4?
YES: Proceed to step 2
NO: Proceed to step 3
2. Fault-tracing information
- Fault-trace according to diagnostic trouble code (DTC) for engine management system, (EFI-243 for Fenix 5.2, EFI-411 for LH 3.2, EFI-411 for Motronic 4.3 or EFI411 for Motronic 4.4). Refer to Powertrain management
- Then continue with step 16





3. Status message
- To get the correct status message carry out the following before reading the DTC:
Ignition ON
Depress Accelerator Pedal (AP) completely. Keep it depressed.
Wait approx. 15 seconds.
- Read out the DTC
- Does the status indicate PERMANENT FAULT?
YES: Proceed to step 4
NO: Proceed to step 18





4. Checking Throttle Position (TP) sensor signal
- Preparation:
Ignition ON
Select scrolling values.
Read off the throttle position sensor signal.
- Fully depress the accelerator pedal several times and check that the throttle position sensor signal increases to approx. 5 volts
- Does the value increase to approx. 5 volts?
YES: Proceed to step 9
NO: Proceed to step 5





5. Connecting the test box
- Preparation:
Ignition OFF
Wait for approx. 150 seconds (only Motronic 4.3 and Motronic 4.4).
- Connect a test box to the automatic Transmission Control Module (TCM) and check ground terminals according to. Connecting the Test Box
- Then continue with step 6





6. Checking signal wiring for short-circuit to battery voltage
- Preparation:
Ignition OFF
Connect the TCM
Disconnect the ECM (Fenix 5.2, LH3.2/EZ129K, Motronic 4.3 or Motronic 4.4).
Ignition ON
- Connect a voltmeter between #50 (#B20) and #20 (#A20) on the test box.
- The voltmeter should register approx. 0 volts
- If reading is OK:
Proceed to step 7
- If reading is incorrect:
Proceed to step 8
7. Checking throttle position sensor circuit
- Check the throttle position sensor circuit according to the relevant information for the ECM installed, refer to Powertrain Management.
Fenix 5.2
DTC EFI-243: Throttle position sensor signal, permanent fault
LH 3.2, EZ1 29K
DTC EFI-411 Throttle position sensor signal, permanent fault, signal too high
Motronic 4.3
DTC EFI-411 Throttle position sensor signal, permanent fault, signal too high
Motronic 4.4
DTC EFI-411 Throttle position sensor signal, permanent fault, signal too high
- Then continue with step 16





8. Checking for short-circuit
- Check the cable between the TCM #B20 and the ECM #B20 of models equipped with Fenix 5.2, LH 3.2, Motronic 4.3 or Motronic 4.4 for a short-circuit to supply voltage according to step 4 of checking for permanent faults. Checking For Permanent Faults
- On models with engine management systems LH 3.2/EZ129K, also check the cable between ECM LH 3.2 #B20 and EZ129K #B20 for a short-circuit to supply voltage according to step 4 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 16





9. Checking voltage drop over the engine control module (ECM) signal ground.
- Preparation:
Ignition OFF
Connect a test box to the ECM, refer to Powertrain Management.
Control modules connected
Ignition ON
Turn on as many power consuming items as possible.
- Connect a voltmeter between ground terminals 31/33 and the test box:
Fenix 5.2:
#42 (#A42) signal ground
LH 3.2:
#20 (#A20) signal ground
Motronic 4.3:
#42 (#A42) signal ground
Motronic 4.4:
#42 (#A42) signal ground Note voltmeter reading.
- Then continue with step 10





10. Connecting test box
- Preparation:
Ignition OFF
Disconnect the test box from the ECM
- Connect test box to the TCM. Connecting the Test Box
- Then continue with step 11





11. Checking voltage drop over the TCM signal ground
- Preparation:
Ignition OFF
Connect the control modules
Ignition ON
Turn on as many power consuming items as possible.
- Connect a voltmeter between ground terminal 31/33 and #20 (#A20) on the test box.
- Make a note of the reading.
- Add the previous reading obtained to the new reading.
- When added together the sum of the two readings should not be more than 0.1 volts
- If reading is OK:
Proceed to step 13
- If reading is incorrect:
Proceed to step 12





12. Checking for contact resistance and oxidation.
- Preparation:
Ignition OFF
- Check ground terminal 31/33 and TCM connectors for contact resistance and oxidation according to step 5 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 16





13. Checking voltage drop over signal ground and power ground
- Preparation:
Ignition ON
Turn on as many power consuming items as possible.
- Connect a voltmeter between #20 (#A20) and #29 (#A29) on the test box.
- The voltmeter should read less than 0.6 volts
- If reading is OK:
Proceed to step 14
- If reading is incorrect:
Proceed to step 15
14. Checking throttle position (TP) sensor circuit
- Check the TP sensor circuit according to the relevant information for the ECM installed, refer to Powertrain Management
Fenix 5.2:
DTC 2-4-3 Throttle position signal, permanent fault
LH 3.2, EZ1 29K MFI control module
DTC 4-1-1 Throttle position sensor signal, permanent fault, signal too high
Motronic 4.3:
DTC 4-1-1 Throttle position sensor signal, permanent fault, signal too high
Motronic 4.4:
DTC EFI-411 Throttle position sensor signal, permanent fault, signal too high
- Then continue with step 16





15. Checking for oxidation and resistance in contacts
- Preparation:
Ignition OFF
- Check ground points 31/32 and 31/33, the cables between the ground points and the control module #A20 and #A29, and the control module connector for contact resistance and oxidation according to step 5 of checking for permanent faults. Checking For Permanent Faults
- Then continue with step 16





16. Verification

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

- Preparation:
Ignition OFF
Reconnect the connectors, reinstall components etc.
Ignition ON
Push down the accelerator pedal (AP) to wide open throttle (WOT) and keep it fully depressed
Wait approx. 15 seconds.
- Read off the status of the DTC
- Does the status indicate INTERMITTENT FAULT?
YES: Fault corrected
NO: Proceed to step 17
17. 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 step 1





18. Intermittent fault
- Check the cable between the TCM #B20 and the ECM #B20 for Fenix 5.2, LH 3.2 and Motronic 4.3 or 4.4 for intermittent short-circuit to supply according to step 4 of checking for intermittent faults. Checking For Intermittent Faults
- On cars with engine management systems type LH 3.2/EZ129K, also check the cable between ECM LH 3.2 #B20 and EZ129K #B20 for an intermittent short-circuit to supply according to step 4 of checking for intermittent faults. Checking For Intermittent Faults
- Check the throttle position sensor circuit according to the relevant information for the ECM installed, refer to Powertrain Management.
Fenix 5.2:
DTC EFI-243 Throttle position sensor signal, intermittent fault
LH 3.2:
DTC EFI-411 Throttle position sensor signal, intermittent fault, signal too high
Motronic 4.3:
DTC EFI-411 Throttle position sensor signal, intermittent fault, signal too high
Motronic 4.4:
DTC EFI-411 Throttle position sensor signal, intermittent fault, signal too high
- Then continue with step 19
19. 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 step 1
NO: Proceed to step Operation done