HX31 - HX40

HX31 - Check FTP Sensor Circuit For Intermittent Short To Ground

- Key on, engine off.
- Access FTPVPID.
- Observe FTP V PID while performing the following:
- Lightly tap on sides of FTP sensor. Do not tap on top of sensor cover because that can result in an incorrect reading or damage to the sensor. This action requires two technicians to lower fuel tank to access the sensor location.
- Wiggle FTP sensor connector and harness between sensor and PCM.
- A fault is indicated by a sudden change in the FTP V PID voltage.

- Key off.

Was a fault indicated?

YES ISOLATE fault and REPAIR as necessary. If FTP sensor is removed from fuel tank or replaced, RERUN EVAP System Leak Test at evaporative test port to VERIFY the repair and PERFORM the Vehicle Preparation for Monitor Repair Verification Drive Cycle and RERUN Evaporative Emission Running Loss Monitor Repair Verification Drive Cycle.
NO UNABLE to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 with the following data: FTP V PID and a list of Possible causes.

HX33 - DTC P0453: Check For High FTP Sensor Voltage

Diagnostic Trouble Code (DTC) P0453 indicates that Self-Test has detected a FTP circuit input above the maximum. Possible causes:
- FTP open.
- FTP short to VREF or VPWR.
- VREF shorted to VPWR.
- SIG RTN open.
- Damaged FTP sensor.
- Damaged PCM.
- Key off.
- Connect scan tool
- Key on, engine off.

NOTE: FTP sensor input with no pressure/vacuum on the fuel tank (fuel filler cap open or not open to atmosphere) is 2.37 to 2.97 volts.

- Access FTPVPID.

Is FTP V PID voltage greater than 4.50 volts?

YES GO to HX34.
NO The fault that produced DTC P0453 is intermittent. GO to HX42.

HX34 - Check FTP Circuit For Short To Power

- Key off.
- Disconnect FTP sensor.
- Key on, engine off.
- Measure voltage between FTP circuit at the FTP sensor harness connector and battery negative post.
- Key off.

Was the voltage greater than 10.5 volts?

YES The FTP is indicating a short to VPWR. GO to HX35.
NO GO to HX36.

HX35 - Check FTP Circuit For Short To VPWR In Harness

- Install breakout box, leave PCM disconnected.
- Key on, engine off.
- Measure the voltage between PCM test pin 62 and PCM test pins 51 and 103.

Is voltage greater than 10.5 volts?

YES REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.
NO REPLACE damaged PCM. RESTORE vehicle. RERUN Quick Test.
HX36 - Check Opposite Induced Low FTP Signal

- Connect a jumper wire between SIG RTN and FTP circuits at the FTP sensor harness connector.
- Key on, engine off.
- If a scan tool communication concern exists, turn the key off, remove jumper immediately and go directly to HX41.
- Access FTPVPID.
- Key off.

Was FTP V PID voltage less than 0.10 volt?

YES REMOVE jumper. GO to HX37.
NO Unable to induce opposite signal. GO to HX39.

HX37 - Check For In Range Voltage Between VREF And SIG RTN Circuits At FTP Sensor

- Key on, engine off.
- Measure the voltage between the VREF circuit and the SIG RTN circuit at the FTP sensor vehicle harness connector.
- Key off.

Was VREF voltage between 4.0 and 6.0 volts?

YES GO to HX38.
NO VREF voltage is out of range. GO to Pinpoint Test Step C1.

HX38 - Check FTP Circuit For Short To VREF In Sensor Or Harness

- Install breakout box, leave PCM disconnected.
- Measure resistance between PCM test pins 62 and 90.

Is the resistance greater than 10,000 ohms?

YES REPLACE damaged FTP sensor. RESTORE vehicle. RERUN EVAP System Leak Test at evaporative test port to VERIFY the repair. PERFORM the Vehicle Preparation for Monitor Repair Verification Drive Cycle and RERUN Evaporative Emission Running Loss Monitor Repair Verification Drive Cycle.
NO REPAIR short circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HX39 - Check FTP Circuit For Open In Harness

- Install breakout box, leave PCM disconnected.
- Measure resistance of FTP circuit between PCM test pin 62 and FTP sensor harness connector.

Is resistance less than 5.0 ohms?

YES GO to HX40.
NO REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.

HX40 - Check For Open SIG RTN Circuit Between PCM And FTP Sensor

- Measure resistance of SIG RTN circuit between PCM test pin 91 and FTP sensor harness connector.

Is resistance less than 5.0 ohms?

YES GO to HX41.
NO REPAIR open circuit. RESTORE vehicle. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.