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 both relays ♦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, plug IV wiring harness (DME control ⇒ Step 3 ness Pin 20, to relays for short module plug) → End to ground ♦Remove relay stage 2 of coolant fan 1 ♦Remove relay stage 2 of coolant fan 2 ♦Measure resistance between special tool 9637 plug IV 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 495 Fan output stage 2 - above limit Diagnosis conditions • Engine running • Battery voltage greater than 7 V • Medium pressure switch (air conditioning) active or engine tem- perature greater than 105 °C • Air conditioning switched on and off once Note! The triggering wire for relays stage 2, terminal 85, is monitored Possible fault cause ♦Short circuit to B+ ♦Relay faulty ♦DME control module faulty 1908 P0481 0-77 page 3 Printed in Germany, 2000 p0481