DD15 - DD24
DD15 - KOEO, KOER DTC P0191 AND CONTINUOUS DTCS 1168,1169: CHECK FUEL PRESSUREDiagnostic Trouble Code (DTC) P0191 indicates the FRP sensor has exceeded the Self-Test Calibration limits and can only be retrieved during KOEO and KOER Self-Test.
DTC P0191: (FRP) circuit malfunction
low limit (gas) 1.6 volts @ 138 kPa (20 psi)
low limit (NG) 1.3 volts @ 586 kPa (70 psi)
high limit (gas) 3.9 volts @ 413 kPa (60 psi)
high limit (NG) 3.7 volts @ 724 kPa (130 psi)
Continuous DTC P1168 indicates the FRP sensor reading is too low. Continuous DTC P1169 indicates the FRP sensor reading is too high. DTC 1168 low limit is 551 kPa (80 psi). DTC 1169 high limit is 896 kPa (130 psi).
Possible causes:
- High fuel pressure.
- Low fuel pressure.
- Damaged FRP sensor.
- Excessive resistance.
- Low or no fuel.
Key on.
Verify there is sufficient fuel (one eighth tank or greater).
Key off.
Fuel pressure gauge connected to Schrader valve.
Key on engine running.
Is the pressure reading within 138 kPa (20 psi) and 413 kPa (60 psi) for gasoline, or 552 kPa (80 psi) and 827 kPa (120 psi) for natural gas vehicles (NG)?
YES GO to DD16.
NO REMOVE pressure gauge. GO to Pinpoint Test Step HC1 for gasoline or HB1 for NG vehicles. HB - Natural Gas Fuel Delivery System HC - Fuel Delivery System
DD16 - CHECK FUEL PRESSURE WITH PID
Connect scan tool.
Install fuel pressure gauge.
Key on.
Access and monitor FRP PID.
Is the FRP pressure reading within 10 PSI of the fuel pressure gauge reading?
YES For DTCS P1168 or P1169: Complete PCM Reset to clear DTCS. DRIVE vehicle 3-5 minutes at a steady speed state. CHECK for Continuous Memory DTC P1168 or P1169. IF P1168 or P1169 is displayed, GO to DD18. All others: RERUN Quick Test.
NO For NG Vehicle: GO to DD18.
All others: GO to DD19.
DD17 - CHECK FUEL PRESSURE WITH FRP PID
Connect scan tool.
Fuel pressure gauge connected.
Key on.
Access and monitor FRP PID.
Is the FRP pressure reading within 10 PSI of the fuel pressure gauge reading?
YES RERUN Quick Test.
NO For NG vehicle: GO to DD18.
All others: GO to DD19.
DD18 - CHECK THAT FUEL RAIL SOLENOID SHUT-OFF VALVE OPENS
Key on.
Access and enter the Output Test Mode.
Cycle output ON and then OFF several times.
Key off.
Was a click felt or heard from the fuel rail solenoid shut-off valve?
YES EXIT Output Test Mode. RECONNECT solenoid valve. GO to DD19.
NO GO to DD22.
DD19 - CHECK VREF VOLTAGE TO FRP SENSOR
Disconnect FRP sensor.
Key on, engine off.
Measure voltage between VREF and SIG RTN circuits at the FRP sensor harness connector.
Key off.
Was the voltage reading between 4.0 and 6.0 volts?
YES GO to DD20.
NO RESTORE vehicle. GO to Pinpoint Test Step C1. C - Reference Voltage (VREF)
DD2O - CHECK FRP CIRCUIT RESISTANCES IN HARNESS
Install breakout box, leave PCM disconnected.
Measure resistance of FRP circuit between PCM test pin (refer to schematic at beginning of pinpoint test for PCM test pin number for FRP circuit) and the FRP sensor at the harness connector.
Measure resistance of SIG RTN circuit between PCM test pin 91 and FRP sensor harness connector.
Measure resistance of VREF circuit between PCM test pin 90 and FRP sensor harness connector.
Is each resistance less than 5.0 ohms?
YES RESTORE vehicle. GO to DD21.
NO REPAIR open or cause of high resistance. RESTORE vehicle. RERUN Quick Test.
DD21 - MONITOR FRP V PID WITH SCAN TOOL
Key on, engine off.
Access and monitor FRP V PID.
Is the FRP V PID value less than 0.2 volt for NG and Continental, and greater than 4-8 volts for Escort/Tracer?
YES REPLACE FRP sensor. RESTORE vehicle. RERUN Quick Test.
NO REPLACE PCM. RESTORE vehicle. RERUN Quick Test.
DD22 - CHECK VPWR VOLTAGE TO FUEL RAIL SOLENOID SHUT-OFF VALVE HARNESS CONNECTOR
Key on.
Access and enter Output Test Mode on the scan tool.
Select: ALL ON.
Disconnect the fuel rail solenoid shut-off valve at the harness connector.
Note: Measurement must be made within 7 seconds of activating test mode.
Measure VPWR circuit voltage between the fuel rail solenoid shut-off valve harness connector and battery negative post.
Is the voltage reading greater than 10.5 volts?
YES GO to DD23.
NO REPAIR open circuit. RESTORE vehicle. RERUN Quick Test.
DD23 - CHECK GROUND CIRCUIT FOR OPEN IN HARNESS
Access and enter Output Test Mode on the scan tool.
Select: ALL ON.
Note: Measurement must be made within 7 seconds of activating test mode.
Measure VPWR voltage between the VPWR and ground circuits at the fuel rail solenoid shut-off valve harness connector.
Is the voltage reading greater than 10.5 volts?
YES REPLACE fuel rail solenoid shut-off valve. RESTORE vehicle. RERUN Quick Test.
NO REPAIR open circuit. RESTORE vehicle. RERUN Quick Test.
DD24 - CHECK VREF VOLTAGE TO FRP SENSOR
Disconnect FRP sensor.
Key on, engine off.
Measure voltage between VREF and SIG RTN circuits at the FRP harness connector.
Is the voltage between 4.0 and 6.0 volts?
YES GO to DD25.
NO VREF is out of range. RECONNECT FRP sensor. GO to Pinpoint Test Step C1. C - Reference Voltage (VREF)
DD25 - CHECK FOR FRP SIGNAL CIRCUIT SHORTED TO SIG RTN OR PWR GND IN HARNESS
Disconnect scan tool from DLC.
Install breakout box, leave PCM disconnected.
Measure resistance of FRP circuit between PCM test pin (refer to schematic at beginning of pinpoint test for PCM test pin number for FRP circuit) and PCM test pins 90, 91, 24, 103
Is the resistance greater than 10,000 ohms?
YES FRP SIG is shorted to SIG RTN or PWR GND in the PCM. REPLACE PCM. RESTORE vehicle. RERUN Quick Test.
NO FRP SIG shorted to SIG RTN or PWR GND in harness REPAIR short. RESTORE vehicle. RERUN Quick Test.