Auto van contact af.
Pen in contact 2 steken (ECU, brandstofsysteem).
Pen in contact 6 steken (EZK, ontsteking).

Auto op contact zetten (positie 2).
Drukknop ingedrukt houden voor circa 2 seconden.
LED zal een drie-cijferige code knipperen.
Drie flitsen, pauze, 2 flitsen, pauze, 1 flits is code 3-2-1.

Na de eerste code nogmaals de drukknop 2 seconden ingedrukt houden.
Komt dezelfde code terug dan is dat de laatste code in het geheugen.

ECU
——————————————————————————————————
1-1-1 – No faults
1-1-2 – ECU internal fault
1-1-3 – Lambda control – engine running too rich/lean
1-2-1 – Mass air flow meter signal faulty or missing
1-2-2 – Air temperature sensor signal faulty or missing
1-2-3 – Coolant temperature sensor signal missing or faulty
1-3-1 – RPM signal from EZK missing
1-3-2 – Battery voltage too low or high
1-3-3 – Throttle position sensor idle setting faulty
1-5-4 – Exhaust Gas Recirculation flow too high
2-1-2 – 02 (lambda) sensor signal missing or faulty
2-1-3 – Throttle position sensor full load setting faulty
2-2-1 – Lambda control – engine running too lean at part load
2-2-2 – Main relay faut
2-2-3 – Idle Air Control valve signal missing
2-3-1 – Lambda control – too lean or too rich at part load
2-3-2 – Lambda control – too lean or too rich at idle
2-3-3 – Idle air flow outside control range
3-1-1 – Speedometer signal to ECU missing
3-1-2 – Knock sensor signal (from EZK) missing
3-2-1 – Cold start injector signal missing or faulty
3-2-2 – Mass Air Flow sensor burn-off signal missing or faulty (MAF wiring fault)
3-4-4 – Exhaust Gas Recirculation temperature signal missing or faulty

EZK
——————————————————————————————————
1-1-1 – No faults
1-4-2 – EZK internal fault
1-4-3 – Knock sensor signal missing or faulty
1-4-4 – Load signal from ECU missing
2-1-4 – RPM sensor signal intermittently missing
2-2-4 – Coolant temperature sensor signal missing or faulty
2-3-4 – Throttle position sensor idle signal faulty