DME 7.8 DME 7.80 · Diagnosis/Troubleshooting

DME 7.8 DME 7.80 Diagnosis/Troubleshooting Note! Secondary air diagnosis can be activated with the Porsche System Tester 2 in the "Short test" menu. Work instruction Display OK If not OK 1 Activate secondary air ♦Remove relay of secondary air Step 3. Step 2. pump injection pump. ♦Jumper terminals 30 and 87. ♦The secondary air pump must be running (audible function). – or ♦Connect and switch on Porsche System Tester 2. ♦Select DME. ♦Call up "Drive links" menu. ♦Select "Secondary air pump". ♦Activate secondary air pump (audible function). 2 Check triggering of sec- ♦Check fuse (Maxi Fuse) of AIR Battery voltage. Check wire from pin ondary air pump pump (on relay carrier 2). 2 to DME control ♦ Remove relay of AIR pump (on module pin III/11 for continuity. relay carrier 2). ♦Measure voltage between pin 3 and ground ♦Push relay back on. ♦Remove connector of AIR pump. Battery voltage. ♦Measure voltage at pin 1 and pin 2 3 Check vacuum system for Seal vacuum sys- leaks tem 4 Check electric change- ♦Remove two-pole connector of Battery voltage. over valve electric change-over valve. ♦ Trigger AIR pump with Porsche System Tester 2. ♦Measure voltage at pin 1 and pin 2 ♦Remove vacuum hose of electric Vacuum must be change-over valve with the present engine running. 0-78.1 page 2 2665 P0491 p0491 Printed in Germany – 6, 2002