Pinpoint Test C : DTC P04B4
WARNING: This page is about a different variant/trim than selected.
- C1 CHECK THE REFUELING VALVE STUCK CLOSED
- The refueling valve opens when the fuel door release button is pressed, to depressurize the fuel tank.
- When the fuel tank release button is pressed and the pressure or vacuum in the tank is higher than a safe refuel range (0.36 Psi (9.97 In.H20)), the refueling valve opens to depressurize the tank to enable a safe refuel (Tank Pressure at 0.25 PSI (6.93 In.H2O)).
- Check for any of the circuit codes (P04B0, P04BA, P04C1, P04C2, P04C9, and P04CD) related to the door operation prior to following the test procedure below.
- If tank pressure already reads close to atmosphere, Skip reading the FTP_H20 DID and move over to B2: FTP Sensor Voltage check else Press the refuel button and read the FTP_H20 PID to see the pressure drop.
- Press the fuel door release button.
- Monitor the DID for a drop in pressure to less than 0.25 PSI (6.92 In.H20).
Does the Tank Pressure drop to less than 0.25 PSI (6.92 In.H20)?
Yes The concern is intermittent, check the connection & wiring issues. No GO to C2 - C2 CHECK THE FTP SENSOR VOLTAGE WITH THE CAPLESS FUEL TANK FILLER PIPE OPENED
- Gently release the fuel door using the mechanical release lever located in the trunk.
- Install the supplemental refueling adaptor provided with the vehicle to open the cap less fuel tank filler pipe.
- KOEO
- Access the PCM and monitor the FTP (VOLT) PID.
Measurement Unit Minimum Pressure Maximum Pressure V 1.4 1.54
Is FTP Voltage reading between 1.4V -1.54 V?
Yes FTP is functioning as intended and concern is intermittent; Please check the wiring and harness for loose connections. No GO to C3 - C3 CHECK IF FTP SENSOR AND CONNECTOR SHOW ANY SIGNS OF FUEL CONTAMINATION.
- Using the diagnostic scan tool, perform a KOEO self test on the PCM.
Does the PID value remain steady?
Yes INSTALL a new FTP sensor. Refer to FUEL TANK PRESSURE SENSOR AND TUBE - HYBRID ELECTRIC VEHICLE (HEV) , FUEL TANK PRESSURE SENSOR AND TUBE - PLUG-IN HYBRID ELECTRIC VEHICLE (PHEV) . No Repair as necessary. Clear any PCM DTC's.