Diagnostic Aids

Perform this test only when directed by QUICK TEST. EFT sensor will operate within the range of -40 to 275°F (-40 to 135°C). This system test is intended to diagnose the following components and circuits:

• EFT Sensor
• Wiring Harness Circuits (EFT & SIG RTN)
• Powertrain Control Module (PCM)

1. 1) KOEO & KOER DTC P0181: Check For KOER DTCs
   
   This DTC indicates EFT sensor voltage fell below or exceeded a calibrated limit and amount of time during self-test. Check for following possible causes:
   • Open or Short Circuit In Wiring Harness
   • Low Ambient Temperature Operation
   • Faulty Harness Connector
   • Faulty EFT Sensor
   • Faulty PCM

   Start engine and bring engine temperature to normal operating temperature. Perform KOER ON-DEMAND SELF-TEST . If DTC P0182 or P0183 is present with DTC P0181, go to next step. If only DTC P0181 is present, clear DTCs. Perform DRIVE CYCLE PROCEDURES  under ADDITIONAL SYSTEM FUNCTIONS. Ensure OBD-II DRIVE CYCLE PROCEDURES are performed to verify repair. Repeat QUICK TEST . If DTC P0181 is still present, go to next step.

2. 2) KOEO & KOER DTC P0180, P0181, P0182 Or P0183: Simulate Opposite EFT Signal To PCM
   
   These DTCs indicate EFT sensor voltage fell below or exceeded a calibrated limit and amount of time during self-test. Check for following possible causes:
   • Open Or Short Circuit In Wiring Harness
   • Low Ambient Temperature Operation
   • VREF Open Or Shorted (P0182)
   • Open Or Short To PWR (P0183)
   • Faulty Wiring Harness Connector
   • Faulty EFT Sensor
   • Faulty PCM

   Turn ignition switch to OFF position. Disconnect EFT sensor connector. With scan tool connected, turn ignition switch to ON position. Using scan tool, select EFTA-V PID from PID/DATA MONITOR & RECORD menu. Record EFTA-V PID measurement. Connect jumper wire between SIG circuit (EFT-A) terminal and SIG RTN terminal at EFT sensor harness connector. See Fig 1.

   NOTE: If scan tool communication link error is displayed, remove jumper wire and go to step  5).

   Record new EFTA-V PID measurement. If EFTA-V PID value is more than 4.5 volts with sensor disconnected and less than .21 volt with jumper wire connected, turn ignition switch to OFF position and replace EFT sensor. If EFTA-V PID value is not as specified, turn ignition switch to OFF position and proceed as follows:

   • If EFTA-V PID measurement is less than 4.5 volts with EFT sensor disconnected and jumper wire removed, go to next step.
   • For DTC P0182, go to next step.
   • If EFTA-V PID measurement is more than .2 volt with EFT sensor disconnected and jumper wire connected, go to step  5).
   • For DTC P0183, go to step  5).

3. 3) Check VREF Circuit Voltage At FRP Sensor
   
   Turn ignition switch to OFF position. Disconnect Fuel Rail Pressure (FRP) sensor connector. Turn ignition switch to ON position. Using a DVOM, measure voltage between FRP sensor harness connector terminals VREF and SIG RTN. See Fig 2. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to TEST C, step  1).
4. 4) Check EFT Circuit For Short To SIG RTN
   
   Turn ignition switch to OFF position. Ensure EFT sensor is disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between PCM harness connector terminals for EFT-A and SIG RTN. See Fig 1. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short circuit.
5. 5) Check EFT Signal For Short To VREF
   
   Using a DVOM, measure resistance between PCM harness connector EFT-A and VREF terminals. See Fig 1. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to VREF circuit.
6. 6) Check EFT SIG & SIG RTN Circuits For Opens
   
   Using a DVOM, measure resistance between PCM harness connector terminal EFT-A and EFT sensor harness connector EFT-A terminal. See Fig 1. Using a DVOM, measure resistance between PCM harness connector SIG RTN terminal and EFT sensor harness connector SIG RTN terminal. If both resistance measurements are less than 5 ohms, replace PCM. If either resistance measurement is 5 ohms or more, repair open in affected circuit.
7. 7) Continuous Memory DTC P0180, P0181, P0182 Or P0183
   
   These DTCs indicate possible intermittent fault. Possible causes for these faults are:
   • Faulty Sensor Or Connector
   • Faulty Wiring Harness
   • Faulty PCM

   Turn ignition switch to ON position. Using scan tool, select EFT-A PID from PID/DATA MONITOR & RECORD menu. While observing PID, tap on sensor and wiggle sensor connector to simulate road shock. If no change in temperature measurement occurs, go to next step. If any change in temperature measurement occurs, inspect connectors for loose, damaged or corroded terminals. Repair as necessary. If connectors are okay, replace EFT sensor.

8. 8) Check Sensor Wiring Harness
   
   While observing EFT-A PID, wiggle and bend small sections of wiring harness working toward PCM. If no change in EFT-A PID temperature measurement occurs, fault is not present at this time. If a large change in EFT-A PID temperature measurement occurs, isolate fault and repair as necessary. Clear DTCs and repeat QUICK TEST .

Fig 1: Identifying Engine Fuel Temperature (EFT) Sensor Connector Terminals

Courtesy of FORD MOTOR CO.

Fig 2: Identifying Fuel Rail Pressure (FRP) Sensor Connector Terminals

Courtesy of FORD MOTOR CO.