Verifying Repairs

Verifying repairs

General
After carrying out repairs it may be necessary to check that the fault really has been remedied. One way of doing this is to check that the engine control module (ECM) has carried out a self diagnostic for the function / component that has been repaired, and that the diagnostic trouble code (DTC) has not recurred.
Verifying repairs is only intended as an aid if uncertain whether the fault persists or not. If an obvious fault is detected during fault-tracing it is not necessary to verify the repair.

Running through the diagnostic operating cycle
Check all diagnostic functions as follows.
- The test must take place on a road with little traffic where it is possible to drive slowly and stop at the side of the road
- For all diagnostics to be carried out, the engine coolant temperature (ECT) must be between -7 °C and +35 °C when the engine is started before the test
- Ensure that there are no diagnostic trouble codes (DTCs) stored in the engine control module (ECM) before carrying out verification.

Schedule:
- Switch on the ignition for 5 seconds
- Switch off the air conditioning (A/C)
- Start the engine. Allow the engine to idle for 10-20 seconds
- Accelerate gently to 70-80 km/h
- Drive at a steady throttle opening at 70-80 km/h for 15 minutes
- Engine brake down to 30 km/h (fully released accelerator pedal (AP))
- Stop the car. Leave the engine running
- Idle the engine for 1 minute
- Accelerate to 70-80 km/h (for manual transmissions, first gear up to 40 km/h in 5 seconds)
- Switch on the air conditioning (A/C)
- Drive at a steady throttle opening at 70-80 km/h for 5 minutes
- Stop the car. Leave the engine running. Read off the data.