Test Procedure
- X1 PRELIMINARY DIAGNOSIS FOR DTCS P0470, P0471, P0472 OR P0473 NOTE: Diagnose and repair EP sensor circuit fault DTCs before addressing range/performance concerns.
- Perform a visual inspection.
- Connect the scan tool.
- Retrieve and record all DTCs.
- Record the freeze frame data.
- Clear the DTCs.
- Perform the key on engine off (KOEO) self-test.
- Perform the key on engine running (KOER) self-test.
ARE DTCS P0470, P0471, P0472 OR P0473 PRESENT?
Yes No For KOEO DTC P0470, Go to X2. Go to X19. For continuous DTC P0470, Go to X60. For DTC P0471, Go to X8. For DTC P0472, Go to X12. For DTC P0473, Go to X16. - X2 DIAGNOSTIC TROUBLE CODE (DTC) P0470
- Possible causes:
- EP sensor
- SIG RTN circuit open or shorted to ground
- PCM
- Key on, engine off.
- Access the EP PID.
IS THE EP PID LESS THAN 127 KPA (18.5 PSI)?
Yes No CLEAR the DTC. REPEAT the KOEO On-Demand Self-Test. If DTC P0470 is present again, Go to X12. Go to X3. If no DTCs are present, CHECK for loose connections, damaged or corroded pins. WIGGLE harness attempting to recreate fault. REFER to SYMPTOM CHARTS - 6.0L DIESEL if driveability concerns exist. - Possible causes:
- X3 CHECK THE EP SENSOR PRESSURE
- Access the EP, MAP, and BARO PIDs.
- Refer to REFERENCE VALUES - 6.0L DIESEL for normal operating values.
IS THE EP PID VALUE WITHIN 10.34 KPA (1.5 PSI) OF THE MAP AND BARO PID VALUES?
Yes No Go to X5. Go to X4. - X4 CHECK THE SIGNAL RETURN CIRCUIT
- Key off.
- Disconnect the EP sensor.
- Disconnect the PCM engine harness connector.
- Measure the resistance between the EP sensor SIG RTN circuit pin A, harness side and the PCM engine harness connector pin 25, harness side.
IS THE RESISTANCE LESS THAN 5 OHMS?
Yes No INSTALL a new EP sensor. REPAIR the circuit. - X5 CHECK THE EP SENSOR CAUTION: Using air pressure greater than 69 kPa (10 psi) may damage the EP sensor.
- Remove the EP sensor.
- Check for contamination, restrictions or carbon build-up in the EP sensor port, mounting bracket or tube. Repair as necessary.
- Check for moisture in the EP sensor port. If moisture is present, use 69 kPa (10 psi) regulated air pressure to remove the moisture.
- Connect the EP sensor connector.
- Connect the PCM connector.
- Key ON, engine OFF.
- Access the BARO, EP, and MAP PIDs.
- Refer to REFERENCE VALUES - 6.0L DIESEL for normal operating values.
IS THE EP PID VALUE WITHIN 10.34 KPA (1.5 PSI) OF THE MAP AND BARO PID VALUES?
Yes No UNABLE to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals.
WIGGLE the harness attempting to recreate the fault.
REPAIR as necessary. REFER to SYMPTOM CHARTS - 6.0L DIESEL if driveability concerns exist.INSTALL a new EP sensor. CLEAR the DTCs. REPEAT the self-test. - X6 CONTINUOUS DIAGNOSTIC TROUBLE CODE (DTC) P0470
- Possible causes:
- EP sensor
- PCM
- Access the EP PID.
- Observe the EP PID while carrying out the following:
- Grasp the vehicle harness close to the EP sensor connector.
- Wiggle and shake the vehicle harness while working toward the PCM.
- Key off.
DOES THE EP PID READING FLUCTUATE?
Yes No ISOLATE the intermittent connection. REPAIR as necessary. Go to X7. - Possible causes:
- X7 INSPECT THE EP SENSOR AND PCM CONNECTORS
- Disconnect the EP sensor.
- Inspect the EP sensor connector and terminals.
- Inspect the PCM connectors.
ARE ALL THE CONNECTIONS OK?
Yes No Unable to duplicate condition. REFER to SYMPTOM CHARTS - 6.0L DIESEL if a driveability concern exists. REPAIR as necessary. - X8 DIAGNOSTIC TROUBLE CODE (DTC) P0471 NOTE: Visually inspect the vehicle for aftermarket accessories and performance modifications (exhaust system, turbocharger, performance chip, etc.). REFER to Diesel Electronic Engine Control (EC) System, MODIFICATIONS TO OBD VEHICLES .
- Possible causes:
- EP sensor
- EP sensor supply tube plugged or restricted
- PCM
- Perform the KOER self-test. If other DTCs are present, repair before continuing. REFER to DIAGNOSTIC TROUBLE CODE (DTC) DESCRIPTIONS .
- Access the EP PID.
- Road test the vehicle performing hard accelerations while monitoring the EP PID.
IS THE EP INCREASE GREATER THAN 25 PSI ?
Yes No Unable to duplicate condition. CHECK for loose connections, damaged or corroded pins. WIGGLE harness attempting to recreate fault. REFER to SYMPTOM CHARTS - 6.0L DIESEL if driveability concerns exist. Go to X9. - Possible causes:
- X9 INSPECT FOR EXHAUST LEAKS
- Inspect the turbo pipe and exhaust manifolds for leaks.
ARE ANY EXHAUST LEAKS PRESENT?
Yes No REPAIR the exhaust leak. Go to X10. - X10 CHECK THE EP SENSOR SUPPLY TUBE
- Inspect the EP sensor supply tube.
IS THE EP SENSOR TUBE RESTRICTED OR PLUGGED?
Yes No INSTALL a new EP sensor tube. Go to X11. - X11 EP SENSOR CHECK
- Disconnect the EP sensor.
- Install the ICP/EBC Adapter Cable D94T-50-A or equivalent between the EP sensor and vehicle harness.
- Key on, engine running.
- Measure the voltage between the EP signal circuit and ground on ICP/EBC Adapter Cable D94T-50 -A.
- Accelerate the engine to wide open throttle (WOT) several times.
IS THE VOLTAGE GREATER THAN 1.35 VOLTS DURING ACCELERATION?
Yes No CLEAR the DTC. REPEAT the self-test. If DTC P0471 is present again, INSTALL a new PCM. INSTALL a new EP sensor. - X12 DIAGNOSTIC TROUBLE CODE (DTC) P0472
- Possible causes:
- EP sensor signal circuit open
- biased sensor
- EP sensor signal circuit shorted to ground
- VREF circuit open
- EP sensor
- PCM
- Key off.
- Disconnect the EP sensor.
- Key on, engine off.
- Measure the voltage between the EP sensor VREF circuit pin B, harness side and ground.
IS THE VOLTAGE BETWEEN 4.5 AND 5.5 VOLTS?
Yes No Go to X13. REPAIR the circuit. - Possible causes:
- X13 CHECK THE EP SENSOR
- Access the EP PID.
- Connect a 5A fused jumper wire between the EP sensor VREF circuit pin B, harness side and the EP sensor signal circuit pin C, harness side.
IS THE EP PID VOLTAGE APPROXIMATELY 4.5 TO 5.5 VOLTS?
Yes No INSTALL a new EP sensor. Go to X14. - X14 CHECK THE SIGNAL CIRCUIT FOR AN OPEN
- Key off.
- Disconnect the PCM engine harness connector.
- Measure the resistance between the EP sensor signal circuit pin C, harness side and the PCM engine harness connector pin 27, harness side.
IS THE RESISTANCE LESS THAN 5 OHMS?
Yes No Go to X15. REPAIR the circuit. - X15 CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between the EP sensor signal circuit pin C, harness side and ground.
IS THE RESISTANCE GREATER THAN 10,000 OHMS?
Yes No INSTALL a new PCM. REPAIR the circuit. - X16 DIAGNOSTIC TROUBLE CODE (DTC) P0473
- Possible causes:
- EP signal shorted to voltage
- SIG RTN circuit open
- EP sensor
- PCM
- Induce the opposite DTC.
- Disconnect the EP sensor.
- Key on, engine off.
- Perform the KOEO On-Demand Self-Test.
IS DTC P0472 PRESENT?
Yes No INSTALL a new EP sensor. Go to X17. - Possible causes:
- X17 CHECK THE EP SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Key off.
- Disconnect the PCM engine harness connector.
- Key on, engine off.
- Measure the voltage between the EP sensor signal circuit pin C, harness side and ground.
IS ANY VOLTAGE INDICATED?
Yes No REPAIR the circuit. Go to X18. - X18 CHECK THE EP SENSOR SIG RTN CIRCUIT FOR AN OPEN
- Key off.
- Measure the resistance between the EP sensor SIG RTN circuit pin A, harness side and the PCM engine harness connector pin 25, harness side.
IS THE RESISTANCE LESS THAN 5 OHMS?
Yes No INSTALL a new PCM. REPAIR the circuit. - X19 CHECK THE EP SENSOR BIAS
- Key on, engine off.
- Access the MAP, BARO and EP sensor PIDs.
IS THE EP PRESSURE WITHIN +/- 3% OF MAP AND BARO PRESSURE?
Yes No CHECK the EP sensor and tube for blockage or restrictions. REPAIR as necessary. REFER to SYMPTOM CHARTS - 6.0L DIESEL if a driveability concern exists. INSTALL a new EP sensor.