LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 233 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P1635: 5-Volt Reference "A" Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for running DTC or within the parameters observed in the Freeze Frame/Failure Records. See CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L MONTANA, SILHOUETTE & VENTURE article.
  3. Turn ignition off. Disconnect the EGR valve electrical connector. Turn ignition on, with engine off. Using a Digital Volt-Ohmmeter (DVOM), measure voltage between the 5-volt reference circuit and engine ground. Does the voltage measure 4.8-5.2 volts? If yes, go to step  5. If no, go to next step.
  4. Does the voltage measure more than 5.2 volts If yes, go to step  8. If no, go to step  6.
  5. Reconnect EGR valve. Disconnect throttle position sensor. Using a DVOM, measure voltage between the 5-volt reference 1 circuit and engine ground. Does the voltage measure 4.8-5.2 volts? If yes, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L MONTANA, SILHOUETTE & VENTURE article. If no, go to step  9.
  6. Monitor DVOM while disconnecting all other devices connected to 5-volt reference circuit one at a time. If voltage changes when one of the above components are disconnected, replace the component. Was a component replaced? If yes, go to step  12. If no, go to next step.
  7. Turn ignition off. Disconnect PCM. Check the 5-volt reference circuit for a short to ground or any sensor low reference circuit. If a problem is found, repair as necessary. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  8. Test all the 5-volt reference circuits and MAP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
  9. Test for a short between the EGR 5-volt reference circuit and EGR solenoid control high circuit. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  10. Replace EGR valve. See REMOVAL & INSTALLATION - MONTANA, SILHOUETTE & VENTURE article. After repairs, go to step  12.
  11. Replace PCM. See REMOVAL & INSTALLATION - MONTANA, SILHOUETTE & VENTURE article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
scientia non olet · About LEMON Manuals