DME 7.8 DME 7.8 0 · Diagnosis/troubleshooting

DME 7.8 DME 7.8 0 Diagnosis/troubleshooting Work instruction Display OK If not OK 1 Check relay ♦Remove relay Approx. 75 Ω Replace relay ⇒ Step 2 → End ♦Measure resistance between Pin 85 and Pin 86 2 Check wiring from DME ♦Connect special tool 9637 to ∞ Ω Repair wiring har- control module to relay wiring harness (DME control ⇒ Step 3 ness for short to ground module plug) → End ♦Remove relay ♦Measure resistance between special tool 9637 plug II Pin 20 and ground 3 Replace DME control module ⇒ Step 4 4 Perform adaptation ♦Switch on the ignition → End ♦Wait one minute ♦Do not press the accelerator ♦Switch off the ignition for at least 10 seconds ♦Read out the fault memory 497 Engine compartment purge fan output stage - short circuit to B+ Diagnosis conditions • Engine running • Battery voltage greater than 7 V • Engine compartment purge fan switched on once • Engine compartment temperature greater than 75 °C • Front and rear lids closed Note! The triggering wire for relay terminal 85 is monitored. The rear lid may be opened to speed up the warming process. In order to proceed with the diagnosis, the rear lid must then be closed. Possible fault cause ♦Short circuit to B+ 1981 P1674 0-200 page 3 Printed in Germany, 2000 p1674