TCS Off Warning Lamp Does Not Come On

Fault symptoms
Lamp test is conducted when ignition is turned on. TCS OFF indicator lamp should be on for about 3 seconds. TCS OFF indicator lamp does not come on.

Conditions
Bus communication must be functioning. See System overview, refer to Description and Operation.

Diagnostic help
The TCS OFF warning lamp can be activated with the diagnostic tool.
- Select "Activate"
- Select "TCS OFF Lamp"

Diagnostic procedure
1. Checking The Switch





Contact TC/ABS control module

Read Value: TCS switch TC/ABS control module
^ The diagnostic tool should display: OFF

^ Hold the TCS switch depressed

Read Value: TCS switch TC/ABS control module
^ The diagnostic tool should display: ON

Is the function Correct?

NO
Go To Step 2

YES
Go To Step 3

2. Checking The Switch's Grounding





Unplug the connector
TCS switch (449)





Connect test lamp 86 11 857 between B+ and pin 7 on the female connector

^ Jiggle the leads and in-line connector at several places and in different directions to reveal intermittent brakes and short circuits in the wiring harness. Observe the multimeter, test lamp or diagnostic tool while doing this.





The test lamp should light.

Is the function Correct?

NO
Go To Step 5

YES
Go To Step 4

3. Checking The Wiring Harness





Unplug the connector:
Main instrument unit 20-pin connector (540)





Turn the ignition switch to the ON position.





Connect test lamp 86 11 857 between B+ and pin 20 on the female connector.

^ Jiggle the leads and in-line connector at several places and in different directions to reveal intermittent brakes and short circuits in the wiring harness. Observe the multimeter, test lamp or diagnostic tool while doing this.

The Test lamp should not light

Activate: TCS Lamp ON

^ Jiggle the leads and in-line connector at several places and in different directions to reveal intermittent brakes and short circuits in the wiring harness. Observe the multimeter, test lamp or diagnostic tool while doing this.

The test lamp should light

Is the function Correct?

NO
Go To Step 8

YES
Go To Step 9

4. Rectifying The Lead





Rectify the TCS switch ground lead.

When the repair is complete
Go To Step 10

5. Checking The Wiring Harness

Read value: TCS switch TC/ABS control module.
^ The diagnostic tool should display: OFF





Connect a jumper lead between pin 5 and 7 of the female connector.

Read value: TCS Switch TC/ABS control module.
^ The diagnostic tool should display: ON

Is the function Correct?

NO
Go To Step 6

YES
Go To Step 7

6. Rectifying The Lead





Repair or replace the lead concerned.

When repair is complete:
Got To Step 10

7. Changing Component





Change the TCS switch
When repair is complete
Go To Step 10

8. Rectifying The Lead





Rectify the lead between pin 20 on the TC/ABS control module and pin 20 on the MIU (K20)

When repair is complete:
Go To Step 10

9. Checking The Wiring Harness

^ Change the TCS lamp in the main instrument unit.

When repair is complete:
Go To Step 10

10. Final Check





^ Clear the diagnostic trouble codes in all systems

^ Carry out a functionality test.

Is the function correct?

NO
Go To Step 11

YES
Go To Step 12

11. Final Check
See Before changing a control module, refer to General Fault Diagnosis.
^ Diagnosis for this fault code is complete.

12. Final Check
The steps taken to correct the fault were correct.
^ Diagnosis is complete.