Faulty Signal

ECM-402A FUEL TANK PRESSURE SENSOR
FAULTY SIGNAL

Checking component



- Check that the fuel tank filler cap is correctly installed and check the sealing ring.
- Ignition on.
- Read fuel tank pressure.
- Start the engine and let it idle.

Activate canister purge (CP) valve. Open and shut the valve. Read the fuel tank pressure and check if the values have changed.

Hint: When the canister purge (CP) valve is open the pressure in the fuel tank drops.

Other information:
- To access/replace the fuel tank pressure sensor, Fuel Tank Pressure Sensor, Replacing
- Fuel tank pressure is measured relative to atmospheric pressure. Maximum pressure is approximately 42 hPa (0.60 psi) and minimum pressure is approx -21 hPa (0.30 psi).

Does the fuel tank pressure change?
Yes - Continue below.
No - Skip to "Checking for Leakage"


Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
--Testing Complete--


Checking for Leakage
Check the hoses and components in the evaporative emission (EVAP) system for leakage according to Check For Air Leaks In the Intake System

Remedy as necessary.
Other information:
- To access/replace the fuel tank pressure sensor, Fuel Tank Pressure Sensor, Replacing


Verification



Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reinstall connectors, components etc.
- Read fuel tank pressure.
- Start the engine and let it idle.
- Activate the EVAP canister shut-off valve and allow it to open.

Activate canister purge (CP) valve. Open and shut the valve. Read the fuel tank pressure and check if the values have changed.

Hint: When the canister purge (CP) valve is open the pressure in the fuel tank drops.


NOTE: If the EVAP canister is full the engine can stop when canister purge (CP) valve activation occurs because of the extra fuel supply.

Does the tank pressure change?
Yes - Testing Complete.
No - Continue below.


Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.