LEMON Manuals: Even more car manuals for everyone
Home >> Volvo >> 2000 >> S70 Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - S70 & V70 Non-Turbo >> Diagnostic Tests >> P1034/ECM-91CF: Engine Control Module Internal Fault >> Diagnostic Procedure

Diagnostic Procedure

  1. DTC can be caused by CAN related problems. Read out fault memory. If DTCs related to CAN exist, repair these first.
  2. Check DTC status to see if fault is intermittent or permanent. Connect a scan tool and start engine. Hold down brake pedal and press accelerator pedal down simultaneously. Fault is intermittent if RPM increases. Fault is permanent if RPM does not increase. If fault is permanent, go to next step.
  3. Connect breakout box. See CONNECTING & DISCONNECTING BREAKOUT BOX .
  4. Check for voltage via fuse for stop lamp switch.See appropriate ENGINE PERFORMANCE WIRING DIAGRAMS article.
  5. Check signal cable between brake light switch terminal No. 2 (Green wire) and ECM terminal B26 for a short to ground and an open circuit and a short circuit to battery supply voltage. Repair as necessary.
  6. Check between ECM terminal A38 and throttle unit terminal No. 2 for a short to ground. Repair as necessary.
  7. Check between ECM terminal A38 and throttle unit terminal No. 2 (Green/Yellow wire) for an open circuit, a short to ground and a short to battery supply voltage. Repair as necessary.
  8. Disconnect breakout box when wiring Diagnostic Procedure is complete. Verify repair. Turn ignition OFF. Ensure all components and connectors are installed correctly. Connect a scan tool and start engine. Hold down brake pedal and press accelerator pedal down simultaneously. Read out fault memory. If DTC is no longer present, repair is complete. If DTC remains, go to next step.
  9. ECM has registered an internal fault. Replace with a known good unit. See REMOVAL & INSTALLATION - EXCEPT S40 & V40 article. Verify repair when complete and clear fault memory. If DTC is no longer present, repair is complete.
scientia non olet · About LEMON Manuals