| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. |
Circuit Description
Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if EVAP system leak is detected or vapor pressure sensor malfunctions. Possible causes are
- Defective vapor pressure sensor.
- Fuel tank cap is installed incorrectly.
- Defective fuel tank cap.
- Damaged, disconnected or blocked vacuum hose.
- Damaged fuel tank.
- Defective charcoal canister.
- Defective fuel tank overfill valve.
Diagnostic Aids
Ask customer if fuel cap has been left off or not been completely tightened recently. This may cause DTC to be set. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.