EXH Lamp Not Working

EXH Lamp Not Working

Fault symptoms
EXH lamp not working.

Diagnostic help
The lamp is grounded in the main instrument unit and supplied with current from the EXH relay.

Checking the wiring harness
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic instrument while carrying out this check.

Diagnostic procedure

1. Checking the lamps
^ Unplug the main instrument unit's 20-pin connector: (540)





^ Connect a test lamp to pin 4 and a good ground.





^ Turn the ignition switch to ON.





^ Remove the EXH relay (relay position D under the left-hand side of the dashboard)





^ Connect a jumper lead between B+ and pin 2 of the EXH relay socket.





^ The test lamp should light up.





Is the function correct?
YES
^ Replace: EXH lamp in MIU.
^ Go to step 3.
NO
^ Go to step 2.

2. Checking the lead
^ Check the lead between pin 4 of the MIU K20 and pin 2 of the EXH relay.





Is the lead OK?
YES
^ Go to step 3
NO
^ Repair or replace the lead
^ Go to step 3

3. Final check
^ Clear diagnostic trouble codes in all systems.





^ Carry out a function check.





Is the function correct?
YES
^ The steps taken to rectify the fault were correct.
NO
^ See Fault diagnosis, general, "Before changing a control module." Before Changing A Control Module