TESTS W/CODES - 3.1L -1998 Chevrolet Monte Carlo
NOTE: For circuit reference, see WIRING DIAGRAMS - 3.1L article.
DTC P1676 - EVAP PURGE VALVE CONTROL CIRCUIT
Circuit Description
The Output Driver Module (ODM) is used by the PCM to turn on many of the current-driven devices that are needed to control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding on. ODM have the capability of diagnosing each output circuit individually.
Conditions required to set DTC are:
Ignition is on. "Â Improper voltage level detected on output circuit controlling EVAP purge solenoid valve. "Â Conditions present for at least 30 seconds. "Â
Diagnostic Procedures
1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK, then go to next step.
2. Turn ignition off. Disconnect PCM connector. Turn ignition on. Using DVOM, check voltage between ground and EVAP purge valve control circuit at PCM connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 6).
3. Set ammeter to 10-amp range. Check current between ground and EVAP purge valve control circuit at PCM connector. Monitor reading for a minimum of 2 minutes. If current is.05-.50 amp, go to step 11). If current is not.05-.50 amp, go to next step.
4. Disconnect EVAP purge valve connector. Using DVOM, check voltage between ground and EVAP purge valve control circuit at harness connector. If voltage reading is zero volts, go to step 10). If voltage reading is not zero volts, go to next step.
5. Locate and repair short to voltage in EVAP purge valve control circuit. After repairs, go to step 16).
6. Turn ignition off. Remove and inspect fuse for EVAP purge valve. If fuse is blown, go to next step. If fuse is okay, go to step 8).
7. Locate and repair short to ground in ignition feed circuit for EVAP purge vent valve. Replace fuse. After repairs, go to step 16).
8. Disconnect EVAP purge valve. Turn ignition on. Check voltage between ground and ignition feed circuit for EVAP purge valve harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 13).
9. Check for an open or short to ground in EVAP purge valve control circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to next step.
10. Check EVAP purge valve control circuit and ignition feed circuit for poor terminal connection at EVAP purge valve and at PCM connector. Repair as necessary. After repairs, go to step 16). If connections are okay, go to step 14).
11. Turn ignition off. Reconnect PCM harness connector. Disconnect EVAP purge valve connector. Turn ignition on. Connect a test light between EVAP purge valve control circuit and ignition feed circuit terminals at EVAP purge valve connector. Using scan tool, select OUTPUTS TEST function and cycle EVAP purge solenoid on and off. If test light flashes on and off. If test light does not flash, go to next step.
12. Check EVAP purge valve control circuit for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 16). If connection is okay, go to step 15).
13. Locate and repair open in ignition feed circuit to EVAP purge valve. After repairs, go to step 16).
14. Replace EVAP purge valve. After replacing valve, go to step 16).
15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off.
16. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for this DTC until this DTC test runs. If scan tool indicates FAILED THIS IGN, repeat step 2). If scan tool does not indicate FAILED THIS IGN, repair is complete.
Wednesday, September 16th, 2009 AT 6:21 AM