2427559 - K64 AIRBAG FAILURE WARNING LIGHT ON

The brake fluid warning light remains on with the handbrake not applied.
The (negative) brake fluid level signal is sent by the special sensor to the Body Computer Node which makes it available via the B-CAN network to the Instrument Panel Node.
The Instrument Panel Node lights up the dedicated warning light and displays the insufficient brake fluid level message; if the warning light is faulty the relevant message is displayed.
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Connect the EXAMINER diagnostic equipment and check the CAN NETWORK INFORMATION:

  • For inactive control units
  • For control units with errors
  • For control units with CAN errors
Continue to Step 5Presence of fault in the CAN Continue as instructed by the tester
Impossible to converse with the Body ComputerContinue to Step 2
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Keeping the Examiner connected, check the plausibility of the brake fluid level parameter at the Body Computer NodeContinue to Step 4The parameter is not plausibleReplace the Body Computer Op. 5505A32Continue to Step 7
Impossible to connect with the Body Computer control unitContinue to Step 2
2ELECTRIC POWER SUPPLY CHECKAll OKProblems metOperation
Check that the Body Computer Node electrical power supply is correct.Continue to Step 3Positive and/or earth electrical power supply fault.Replace the defective component (if a fuse is involved, search for the cause of the problem).
3CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Using the Examiner, check the possibility of connecting with the Body Computer Node. Continue to Step 1Impossible to connect with the Body Computer control unitReplace the Body Computer Op. 5505A32
4CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisThe fault persistsContinue to Step 5
5BRAKE FLUID LEVEL CHECKAll OKProblems metOperation
Check that the brake fluid level is not lowContinue to Step 9Brake fluid level too low Continue to Step 6
6TOP UP BRAKE FLUID LEVELAll OKProblems metOperation
Restore the brake fluid level and check that the warning light goes outEnd of diagnosisThe warning light does not go off Continue to Step 7
7CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Keeping the diagnostic equipment connected, check that there are no CAN errors at the BRAKE NODEContinue to Step 8Presence of faults at the C-CANContinue to Step 14
8CHECKING ELECTRICAL EQUIPMENTAll OKProblems metOperation
Disconnect the connector from the fluid level sensor and, using a multimeter, check the efficiency of the connection to earth See   E4010  INSTRUMENT PANEL Continue to Step 9Faulty earthRestore earth connection efficiency See   E4010  INSTRUMENT PANEL
9CHECKING ELECTRICAL EQUIPMENTAll OKProblems metOperation
Check the continuity of the cable from the connector to the Body computer See   E4010  INSTRUMENT PANEL Continue to Step 10Cable brokenRestore connection See   E4010  INSTRUMENT PANEL
10CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the Examiner and check the plausibility, at the Body Computer Node, of the handbrake applied parameterContinue to Step 11The parameter is not plausibleContinue according to the instructions for the See table   K72  HANDBRAKE APPLIED WARNING LIGHT
11CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the Examiner or keep it connected and check the operation of the brake fluid level warning light at the Instrument Panel Node through active diagnosisContinue to Step 12The warning light does not flashReplace instrument panel Op. 5560B11
12ELECTRIC POWER SUPPLY CHECKAll OKProblems metOperation
Check that the Instrument Panel Node electrical power supply is correct.Continue to Step 13Positive and/or earth electrical power supply fault. Replace the defective component (if a fuse is involved, search for the cause of the problem).
13CHECK ELECTRICAL CONNECTIONSAll OKProblems metOperation
Check the electrical connections between the Body Computer and the Instrument Panel, in particular that each individual pin is correctly connected.Continue to Step 14Electrical connections not working.Restore damaged electrical connection.
14CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Keeping the Examiner connected, check the plausibility of the brake fluid level parameter at the Body Computer NodeContinue to Step 15The parameter is not plausibleReplace the Body Computer Op. 5505A32
15CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer present End of diagnosisFault persists Replace the brake fluid reservoir and sensor Op.   3330C30