DTC P1401[AJ (3.0L Duratec)]

DTC P1401	Differential Pressure Feedback (D.P.F.) EGR sensor high voltage detected
DETECTION CONDITION	• The PCM monitors the D.P.F. EGR sensor output voltage at PCM terminal 65. If the PCM detects that average D.P.F. EGR sensor voltage goes to a voltage less than the maximum calibrated value, the PCM determines that the D.P.F. EGR sensor circuit high voltage.
POSSIBLE CAUSE	• Open circuit in wiring between D.P.F. EGR sensor terminal C and PCM terminal 65 • Short to power in wiring between D.P.F. EGR sensor terminal A and PCM terminal 90 • Damaged D.P.F. EGR sensor • Short to power in wiring between D.P.F. EGR sensor terminal C and PCM terminal 65 • Open circuit in wiring between D.P.F. EGR sensor terminal B and PCM terminal 91 • Damaged PCM

DTC P1401

Differential Pressure Feedback (D.P.F.) EGR sensor high voltage detected

DETECTION CONDITION

• The PCM monitors the D.P.F. EGR sensor output voltage at PCM terminal 65. If the PCM detects that average D.P.F. EGR sensor voltage goes to a voltage less than the maximum calibrated value, the PCM determines that the D.P.F. EGR sensor circuit high voltage.

POSSIBLE CAUSE

• Open circuit in wiring between D.P.F. EGR sensor terminal C and PCM terminal 65

• Short to power in wiring between D.P.F. EGR sensor terminal A and PCM terminal 90

• Damaged D.P.F. EGR sensor

• Short to power in wiring between D.P.F. EGR sensor terminal C and PCM terminal 65

• Open circuit in wiring between D.P.F. EGR sensor terminal B and PCM terminal 91

• Damaged PCM

STEP	INSPECTION	ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
No	Record the FREEZE FRAME DATA on the repair order, then go to next step.
2	VERIFY SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service Information. If the vehicle is not repaired, go to next step.
No	Go to the next step.
3	INDETIFY TRIGGER DTC FOR FEEZE FRAME DATA • Is DTC P1401 on FREEZE FRAME DATA?	Yes	Go to the next step.
No	Go to FREEZE FRAME DATA DTC inspection. (See DTC TABLE[AJ (3.0L Duratec)].)
4	DETERMINE PRESENT DPFEGR PID VOLTAGE • Turn the ignition switch to the ON position. • Access DPFEGR PID with M-MDS. • Is DPFEGR PID voltage greater than 4.0 V?	Yes	Go to the next step.
No	Go to Step 12.
5	CHECK D.P.F EGR CIRCUIT FOR SHORT TO PWR • Disconnect D.P.F. EGR sensor. • Key on, engine off. • Measure voltage between D.P.F. EGR circuit at the D.P.F. EGR sensor harness connector and chassis ground. • Is the voltage greater than 10.5 V?	Yes	Go to the next step.
No	Go to Step 7.
6	CHECK D.P.F EGR CIRCUIT FOR SHORT TO PWR IN HARNESS • Disconnect PCM. • Turn the ignition switch to the ON position. • Measure voltage between D.P.F. EGR circuit at the PCM harness connector and the battery negative post. • Is the voltage greater than 10.5 V?	Yes	Repair short to power circuit, then go to Step 13.
No	Replace PCM, then go to Step 13.
7	INDUCE OPPOSITE D.P.F. EGR SENSOR VOLTAGE • Connect a jumper wire between terminal B and C at the D.P.F. EGR sensor harness side connector. Note • If a scan tool communication concern exists, key off, remove jumper immediately and go to Step 11. • Access DPFEGR PID. • Is DPFEGR PID voltage less than 0.05 V?	Yes	Go to the next step.
No	Unable to induce opposite signal. Go to Step 9.
8	CHECK VREF VOLTAGE TO D.P.F. EGR SENSOR • Measure voltage between terminal A and B at the D.P.F. EGR sensor harness connector. • Is VREF voltage 4.0—6.0 V?	Yes	Go to the next step.
No	Go to symptom troubleshooting “No.27 CONSTANT VOLTAGE” diagnostic procedure. (See NO.27 CONSTANT VOLTAGE[AJ (3.0L Duratec)].)
9	CHECK D.P.F EGR CIRCUIT FOR OPEN IN HARNESS • Disconnect PCM. • Measure resistance of D.P.F. EGR circuit between PCM terminal 65 and D.P.F. EGR sensor terminal C at harness side connector. • Is resistance less than 5.0 ohms?	Yes	Go to the next step.
No	Repair open circuit, then go to Step 13.
10	CHECK SIG RTN CIRCUIT FOR OPEN IN HARNESS • Measure resistance of SIR RTN circuit between PCM terminal 91 and D.P.F. EGR sensor terminal 65 at harness side connector. • Is resistance less than 5.0 ohms?	Yes	Replace PCM, then go to Step 13.
No	Repair open circuit, then go to Step 13.
11	CHECK D.P.F EGR CIRCUIT FOR SHORT TO VREF IN HARNESS • Disconnect PCM. • Measure resistance between PCM terminal 65 and 90 at the PCM harness connector. • Is resistance greater than 10,000 ohms?	Yes	Replace D.P.F. EGR sensor, then go to Step 13.
No	Short to VREF circuit, then go to Step 13.
12	COMPLETE A WIGGLE TEST ON D.P.F. EGR SENSOR AND CIRCUIT WHILE MONITORING DPFEGR PID FOR A SUDDEN CHANGE • While monitoring DPFEGR PID, tap on the D.P.F. EGR sensor and wiggle the wiring while looking for a sudden change in value as an indication of an intermittent. • Is intermittent fault found?	Yes	Repair or replace malfunctioning part, then go to the next step.
No	Unable to duplication or identify fault at this time. Go to the next step.
13	VERIFY TROUBLESHOOTING OF DTC P1401 COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. • Perform KOEO/KOER self test. (See KOEO/KOER SELF TEST[AJ (3.0L Duratec)].) • Is the PENDING CODE same DTC present?	Yes	Replace PCM, then go to next step. (See PCM REMOVAL/INSTALLATION[AJ (3.0L Duratec)].)
No	Go to the next step.
14	VERIFY AFTER REPAIR PROCEDURE • Perform "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE[AJ (3.0L Duratec)].) • Is there any DTC present?	Yes	Go to applicable DTC inspection. (See DTC TABLE[AJ (3.0L Duratec)].)
No	Troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

Record the FREEZE FRAME DATA on the repair order, then go to next step.

VERIFY SERVICE INFORMATION AVAILABILITY

• Verify related Service Information availability.

• Is any related Service Information available?

Yes

Perform repair or diagnosis according to the available Service Information. If the vehicle is not repaired, go to next step.

Go to the next step.

INDETIFY TRIGGER DTC FOR FEEZE FRAME DATA

• Is DTC P1401 on FREEZE FRAME DATA?

Yes

Go to the next step.

Go to FREEZE FRAME DATA DTC inspection.

(See DTC TABLE[AJ (3.0L Duratec)].)

DETERMINE PRESENT DPFEGR PID VOLTAGE

• Turn the ignition switch to the ON position.

• Access DPFEGR PID with M-MDS.

• Is DPFEGR PID voltage greater than 4.0 V?

Yes

Go to the next step.

Go to Step 12.

CHECK D.P.F EGR CIRCUIT FOR SHORT TO PWR

• Disconnect D.P.F. EGR sensor.

• Key on, engine off.

• Measure voltage between D.P.F. EGR circuit at the D.P.F. EGR sensor harness connector and chassis ground.

• Is the voltage greater than 10.5 V?

Yes

Go to the next step.

Go to Step 7.

CHECK D.P.F EGR CIRCUIT FOR SHORT TO PWR IN HARNESS

• Disconnect PCM.

• Turn the ignition switch to the ON position.

• Measure voltage between D.P.F. EGR circuit at the PCM harness connector and the battery negative post.

• Is the voltage greater than 10.5 V?

Yes

Repair short to power circuit, then go to Step 13.

Replace PCM, then go to Step 13.

INDUCE OPPOSITE D.P.F. EGR SENSOR VOLTAGE

• Connect a jumper wire between terminal B and C at the D.P.F. EGR sensor harness side connector.

Note

• If a scan tool communication concern exists, key off, remove jumper immediately and go to Step 11.

• Access DPFEGR PID.

• Is DPFEGR PID voltage less than 0.05 V?

Yes

Go to the next step.

Unable to induce opposite signal. Go to Step 9.

CHECK VREF VOLTAGE TO D.P.F. EGR SENSOR

• Measure voltage between terminal A and B at the D.P.F. EGR sensor harness connector.

• Is VREF voltage 4.0—6.0 V?

Yes

Go to the next step.

Go to symptom troubleshooting “No.27 CONSTANT VOLTAGE” diagnostic procedure.

(See NO.27 CONSTANT VOLTAGE[AJ (3.0L Duratec)].)

CHECK D.P.F EGR CIRCUIT FOR OPEN IN HARNESS

• Disconnect PCM.

• Measure resistance of D.P.F. EGR circuit between PCM terminal 65 and D.P.F. EGR sensor terminal C at harness side connector.

• Is resistance less than 5.0 ohms?

Yes

Go to the next step.

Repair open circuit, then go to Step 13.

CHECK SIG RTN CIRCUIT FOR OPEN IN HARNESS

• Measure resistance of SIR RTN circuit between PCM terminal 91 and D.P.F. EGR sensor terminal 65 at harness side connector.

• Is resistance less than 5.0 ohms?

Yes

Replace PCM, then go to Step 13.

Repair open circuit, then go to Step 13.

CHECK D.P.F EGR CIRCUIT FOR SHORT TO VREF IN HARNESS

• Disconnect PCM.

• Measure resistance between PCM terminal 65 and 90 at the PCM harness connector.

• Is resistance greater than 10,000 ohms?

Yes

Replace D.P.F. EGR sensor, then go to Step 13.

Short to VREF circuit, then go to Step 13.

COMPLETE A WIGGLE TEST ON D.P.F. EGR SENSOR AND CIRCUIT WHILE MONITORING DPFEGR PID FOR A SUDDEN CHANGE

• While monitoring DPFEGR PID, tap on the D.P.F. EGR sensor and wiggle the wiring while looking for a sudden change in value as an indication of an intermittent.

• Is intermittent fault found?

Yes

Repair or replace malfunctioning part, then go to the next step.

Unable to duplication or identify fault at this time. Go to the next step.

VERIFY TROUBLESHOOTING OF DTC P1401 COMPLETED

• Make sure to reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

• Perform KOEO/KOER self test.

(See KOEO/KOER SELF TEST[AJ (3.0L Duratec)].)

• Is the PENDING CODE same DTC present?

Yes

Replace PCM, then go to next step.