Signal Too Low. Permanent Fault
Signal too low. Permanent fault
EFI-335 Cable fault between AW 50-42 and Motronic 4.4 (lamp lights)
Checking cable
- Check cable between engine control module (ECM) #B26 and transmission control module (TCM) #B15 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select "Continue" when the fault has been repaired.
Continue - Verification
Fault-tracing information
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Verification
Verify
Verification of repair
Verification of repair
Hint: After a repair, it may be necessary to check that the fault is properly rectified.
One way of doing this is to check that the ECM has conducted its own diagnosis for the specific function/component which has been repaired without recurrence of the fault.
- Ignition off.
- Reconnect connectors, components etc.
- Shut off ST by setting switch on adapter lead box to "OFF".
- Disconnect ST from VIDA cart.
Press Continue.
Continue - Volvo System Tester as verification tool
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Volvo System Tester as verification tool
It is possible to check the ECM's self-diagnosis by using the Volvo System Tester. The Diagnosis Test features a menu called Diagnosis Check. Enter this menu and you come first to a status menu, where it is possible to see if all the conditions which the ECM works with have been met or not.
As regards repair verification, it may be of value to see if a TRIP has occurred or not.
TRIP=YES
All the diagnosis functions have been undertaken at least once during one and the same run.
TRIP=NO
All diagnosis is not yet complete, a sub-menu shows which diagnosis functions are not yet ready.
REPLACEMENT TRIP
The ECM has not been able to implement all diagnosis since certain fault codes have prevented another diagnosis.
If a TRIP is not completed, press ENTER in this menu to view which functions have not been tested. This menu only shows those functions which are not tested, if any function is tested while this menu is active, the status is changed to TESTED.
Most functions/components are tested when the engine is started and the test continues as long as the engine is running. A few other functions require that certain pre-conditions are met before tests can be carried out. For example, in order to diagnose the TWC, the front and rear HO2S are used, so these must be tested before the TWC can be tested, otherwise the results will be entirely misleading.
Press Continue.
Continue - DONE
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DONE - Verification in the workshop
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Verification in the workshop
Verification in the workshop
- If the control module has been without voltage supply during the fault tracing process, the engine should be started a few times before verification is carried out.
- Ensure that there are no DTCs stored in the system before verification is carried out.
- The A/C shall be off.
- Start the engine and let it run at idling speed.
Use the diagnostic check menu in the Volvo System Tester to check if the control module has carried out its self-diagnosis. Self-diagnosis for 3-1-5 (EVAP system), for example, may take up to 20 minutes with the engine at idling speed.
If the control module has carried out its self-diagnosis and the DTC has not recurred, the fault has in all probability been rectified.
Note! DTC 1-2-3 ECT sensor signal, faulty signal
- In order for this diagnosis to be carried out, the engine must be started at an engine temperature lower than +28 °C.
DTC 5-1-4 Engine cooling fan half speed, signal
- This DTC is checked only when the control module tries to activate the engine cooling fan.
DTC 3-2-5 Memory loss.
- This DTC appears immediately when the control module is connected to the voltage supply after a memory loss.
Self-diagnosis should have been carried out and DTC should not have been set.
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