Signal Too High. Permanent Fault

Safety
- See Safety instructions for handling fuel.
- Proceed to: Checking Ground Lead section below.





Checking Ground Lead
- Ignition OFF.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect tank pressure sensor.
- Connect an ohmmeter between fuel tank pressure sensor connector terminal 2 (engine control module (ECM) side) and ground.
- The ohmmeter should read approximately 0 ohms.

If reading is OK:
^ Proceed to: Checking The Signal Cable section below.

If reading is incorrect:
^ Proceed to: Checking Connector section below.





Checking Connector
- Ignition OFF.
- Tank pressure sensor disconnected.
- Check control module connector and connector A1/A for contact resistance and oxidation and remedy.
- Control module connected.
- Connect connector A1/A.
- Connect an ohmmeter between fuel tank pressure sensor connector terminal 2 (engine control module side) and ground.
- The ohmmeter should read approximately 0 ohms.

If reading is OK:
^ Proceed to: Verification section below.

If reading is incorrect:
^ Proceed to: Checking Cable section below.





Checking Cable
- Check ground lead between fuel tank pressure sensor terminal 2 and control module terminal # A18 for an open-circuit.
- Remedy as necessary.
- Proceed to: Verification section below.





Checking The Signal Cable
- Ignition ON.
- Tank pressure sensor disconnected.
- Connect a voltmeter between fuel tank pressure sensor connector terminal 3 (engine control module side) and ground.
- The voltmeter should read 5 - 6 Volts.

If reading is OK:
^ Proceed to: Checking Fuel Tank Pressure Sensor section below.

If value is lower:
^ Proceed to: Checking Connector section below.

If value is higher:
^ Proceed to: Checking Cable section below.





Checking Cable
- Check signal cable between fuel tank pressure sensor terminal 3 and control module terminal # B31 for a short-circuit to supply voltage.
- Remedy as necessary.
- Proceed to: Verification section below.





Checking Connector
- Ignition OFF.
- Tank pressure sensor disconnected.
- Check control module connector and connector A1/B for contact resistance and oxidation and remedy.
- Control module connected.
- Connect connector A1/B.
- Ignition ON.
- Connect a voltmeter between tank pressure sensor connector terminal 3 (engine control module side) and ground.
- The voltmeter should read approximately 5 - 6 Volts.

If reading is OK:
^ Proceed to: Verification section below.

If reading is incorrect:
^ Proceed to: Checking Cable section below.





Checking Cable
- Check signal cable between fuel tank pressure sensor terminal 3 and control module terminal B31 for an open-circuit.
- Remedy as necessary.
- Proceed to: Verification section below.





Checking Fuel Tank Pressure Sensor
- Ignition OFF.
- Connect fuel tank pressure sensor.
- Start the engine and idle it for a minute.
- Read diagnostic trouble code (DTC) status message.
- Is an intermittent fault displayed?

Yes:
^ Proceed to: Remedy Connector section below.

No:
^ Proceed to: Replacing Component section below.

Replacing Component
- Try a new fuel tank pressure sensor.
- Proceed to: Verification section below.

Remedy Connector
- The diagnostic trouble code has been caused by loose connections in the fuel tank pressure sensor connector.
- Check connector for contact resistance and oxidation and remedy.
- Proceed to: Verification section below.





Verification
After carrying out the repair, check that the fault has been remedied as follows:

- Ignition OFF.
- Ensure that fuel tank pressure sensor, air conditioning pressure sensor, accelerometer and engine control module are connected.
- Connector A1/A and A1/B connected.
- Start the engine and idle it.

- If EFI-621 is stored it should have intermittent status.
- Does EFI-621 have intermittent status?

Yes:
^ Fault corrected.

No:
^ Fault not found.