Signal Too High. Permanent Fault

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 1 (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 next step below.















Checking connector
- Ignition off.
- Tank pressure sensor disconnected.
- Check connector 24/4 for contact resistance and oxidation.
- Control module connected.
- Connect connector 24/4.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 1 (engine control module (ECM) 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 next step below.











Checking cable
Check ground lead between fuel tank pressure sensor terminal 2 and control module terminal #B28 for an open-circuit. Remedy as necessary.

Then continue with:
^ Verification section below.











Checking the signal cable
- Ignition on.
- Tank pressure sensor disconnected.
Connect a voltmeter between fuel tank pressure sensor connector terminal 2 (engine control module (ECM) 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 next step below.











Checking cable
Check signal cable between fuel tank pressure sensor terminal 2 and engine control module (ECM) terminal #B31 for a short-circuit to supply voltage. Remedy as necessary.

Then continue with:
^ Verification section below.












Checking connector
- Ignition off.
- Tank pressure sensor disconnected.
- Check control module connector and connectors 24/2 and 24/4 for contact resistance and oxidation and remedy.
- Control module connected.
- Connect connectors 24/2 and 24/4.
- Ignition on.
Connect a voltmeter between tank pressure sensor connector terminal 2 (engine control module (ECM) side) and ground.

The voltmeter should read approximately 5 Volts.

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

If reading is incorrect:
^ Proceed to next step below.












Checking cable
Check signal cable between fuel tank pressure sensor terminal and control module terminal #B31 for an open-circuit.

Then continue with:
^ 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 next step below.


Replacing component
Try a new fuel tank pressure sensor. See: Fuel Tank Pressure Sensor.

Then continue with:
^ Verification section below.

Remedy connector
The diagnostic trouble code (DTC) has been caused by loose connections in the fuel tank pressure sensor connector. Check the connector for contact resistance and oxidation and remedy.

Then continue with:
^ Proceed to next step below.









Verification


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


- Ignition off.
- Ensure that fuel tank pressure sensor, air conditioning (A/C) pressure sensor, accelerometer and engine control module (ECM) are connected.
- Connectors 24/2 and 24/4 are 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