DTC P0401[AJ (3.0L Duratec)]

DTC P0401	EGR flow insufficient detected
DETECTION CONDITION	• The PCM monitors EGR system during steady state driving conditions while the EGR is commanded on. If the signal from differential pressure feedback (D.P.F.) EGR sensor indicates that EGR flow is less than the desired minimum, the PCM determines EGR flow insufficient detected.
POSSIBLE CAUSE	• Vacuum hose malfunction (damaged, insufficient connected) • EGR valve stuck close • Vacuum leakage at EGR valve • EGR flow pass restricted • Short to power supply circuit in wiring EGR control valve terminal B and PCM terminal 47 • Open circuit in wiring between EGR control valve terminal B and PCM terminal 47 • Open circuit in wiring between EGR control valve terminal A and main relay terminal B • Open circuit in wiring between D.P.F. EGR sensor terminal A and PCM terminal 90 • D.P.F. EGR sensor downstream hose off or plugged • D.P.F. EGR sensor hoses both off • D.P.F. EGR sensor hoses connected reverse • EGR orifice tube damaged • Damaged EGR control valve • Damaged PCM

DTC P0401

EGR flow insufficient detected

DETECTION CONDITION

• The PCM monitors EGR system during steady state driving conditions while the EGR is commanded on. If the signal from differential pressure feedback (D.P.F.) EGR sensor indicates that EGR flow is less than the desired minimum, the PCM determines EGR flow insufficient detected.

POSSIBLE CAUSE

• Vacuum hose malfunction (damaged, insufficient connected)

• EGR valve stuck close

• Vacuum leakage at EGR valve

• EGR flow pass restricted

• Short to power supply circuit in wiring EGR control valve terminal B and PCM terminal 47

• Open circuit in wiring between EGR control valve terminal B and PCM terminal 47

• Open circuit in wiring between EGR control valve terminal A and main relay terminal B

• Open circuit in wiring between D.P.F. EGR sensor terminal A and PCM terminal 90

• D.P.F. EGR sensor downstream hose off or plugged

• D.P.F. EGR sensor hoses both off

• D.P.F. EGR sensor hoses connected reverse

• EGR orifice tube damaged

• Damaged EGR control valve

• 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 P0401 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	RUN KEY ON ENGINE OFF (KOER) SELF TEST • Perform the KOER self test. (See KOEO/KOER SELF TEST[AJ (3.0L Duratec)].) • Is KOER DTC P1408 output?	Yes	Go to the next step.
No	Go to Step 10.
5	RETRIEVE CONTINUOUS MEMORY DTCS Note • If any DTC other than DTC P1406 is output, record DTC and refer to DTC table. • Retrieve continuous memory DTCs. • Is DTC P1406 displayed?	Yes	Go to Step 16.
No	Go to the next step.
6	RUN KOER SELF TEST WHILE MONITORING EGR VACUUM • Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge. Note • Since the EGR vacuum hose is disconnected, ignore DTCs during this KOER self test. • Run KOER self test while monitoring gauge. • Approximately 30 seconds into test, EGR flow will be requested for a few seconds. • The vacuum at this time should increase above 5.4 kPa {1.6 inHg} to open the valve. • Does the vacuum increase to 10 kPa {3.0 inHg} or greater at any time during KOER self test?	Yes	Go to the next step.
No	Go to Step 10.
7	INSPECT D.P.F. EGR SENSOR PRESSURE HOSES • Visually inspect both pressure hoses for reserved connection at D.P.F. EGR sensor or at orifice tube assembly. • Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze. • Inspect D.P.F. EGR sensor and orifice tube assembly for blockage or damage at the pickup tubes. • Is fault detected?	Yes	Repair pressure hose, then go to Step 25.
No	Go to the next step.
8	CHECK D.P.F. EGR SENSOR OUT PUT BY APPLYING VACUUM WITH HAND PUMP • Connect the M-MDS to DLC-2. • Disconnect pressure hoses at D.P.F. EGR sensor. • Connect a hand vacuum pump to the downstream connection at sensor (intake manifold side of sensor or smaller diameter pickup tube.) • Turn the ignition switch to the ON position. • Disconnect pressure hoses at D.P.F. EGR sensor. • Access DPFEGR PID and note PID value. • Apply 27—30 kPa {8—9 inHg}vacuum to the D.P.F. EGR sensor and hold for a few seconds. • Quickly release vacuum. ― The DPFEGR PID voltage must be between 0.2 and 1.3 V with the ignition switch ON and no vacuum applied. ― The DPFEGR PID voltage must increase to greater than 4.0 V with the vacuum applied. ― The DPFEGR PID must drop to less than 1.5 V in less than 3 seconds when vacuum is released. • Does DPFEGR PID voltage indicate a fault in the D.P.F. EGR sensor?	Yes	Replace D.P.F. EGR sensor.
No	Go to the next step.
9	CHECK EGR VALVE FUNCTION BY APPLYING VACUUM WITH HAND PUMP • Disconnect vacuum hose at EGR valve and plug hose. • Connect a hand vacuum pump to EGR valve. • Start the engine and bring to idle. • Access DPSEGR and RPM PIDs. • Slowly apply 27—34 kPa {210—250 mmHg, 8.0—10 inHg} vacuum to the D.P.F. EGR sensor and hold for 10 seconds. If engine want to stall increase engine speed with throttle to maintain a minimum of 1,000 rpm. • Look for the following: • Access DPFEGR and RPM PIDs. ― EGR valve starts opening at about 5.4 kPa {41 mmHg, 1.6 inHg} vacuum indicated by increasing D.P.F.EGR voltage. ― DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID must read 2.5 V minimum with full vacuum applied. ― DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source can be leaking. • Does the DPFEGR PID voltage indicate that the EGR valve is opening as described in this test?	Yes	Go to Step 15.
No	Remove and inspect the EGR valve for signs of contamination, unusual wear, carbon deposits, binding and other damage. If the EGR valve is normal, look for an obstruct EGR valve port in the intake manifold or plugged orifice tube assembly. Repair or replace malfunctioning part. Then go to Step 25.
10	CHECK VACUUM SOURCE AND VACUUM HOSES TO AND FROM EGR CONTROL VALVE • Inspect vacuum lines between vacuum source and EGR control valve and between EGR control valve and EGR valve for leaks, kinks, disconnects, blockage, routing or any damage. • Disconnect vacuum hoses at EGR control valve. • Connect EGR control valve vacuum source hose to a vacuum gauge. • With engine warm and at idle, take vacuum gauge reading. • Is the vacuum gauge reading a minimum of 51 kPa {390 mmHg, 15 inHg} at idle and vacuum lines normal?	Yes	Go to the next step.
No	Isolate fault and repair or replace malfunctioning part, according to inspection result. Then go to Step 25.
11	CHECK PWR VOLTAGE TO EGR CONTROL VALVE • Disconnect EGR control valve. • Turn the ignition switch to the ON position. • Measure voltage at EGR control valve terminal A and harness connector. • Is the voltage greater than 10.5 V?	Yes	Go to the next step.
No	Repair or replace open circuit, then go to Step 25.
12	CHECK EGR CONTROL VALVE RESISTANCE • Measure EGR control valve resistance. • Is the resistance 26—40 ohms?	Yes	Go to the next step.
No	Replace EGR control valve, then go to Step 25.
13	CHECK EGR CONTROL VALVE CONTROL CIRCUIT SHORT TO POWER IN HARNESS • Disconnect PCM. • Turn the ignition switch to the ON position. • Measure voltage between PCM harness side connector terminal 47 and battery negative post. • Is voltage greater than 1.0 V?	Yes	Repair short circuit, then go to Step 25.
No	Go to the next step.
14	CHECK EGR CONTROL VALVE CIRCUIT FOR OPEN IN HARNESS • Measure resistance of between EGR control valve terminal B and PCM terminal 47 at harness side connector. • Is the resistance less than 5.0 ohms?	Yes	Go to the next step.
No	Repair open circuit, then go to Step 25.
15	CHECK EGR CONTROL VALVE VACUUM OUTPUT CAPABILITY BY GRIUNDUNG EGR CONTROL VALVE CONTROL CIRCUIT • Disconnect vacuum hose at the EGR valve and connect to a vacuum gauge. • Start the engine and run it at idle. • With engine at idle, jumper PCM terminal 47 to chassis ground. • Is vacuum gauge reading 13.5 kPa {110 mmHg, 4.0 inHg}?	Yes	Replace PCM, then go to Step 25.
No	Replace EGR control valve, then go to Step 25.
16	INPECT DOWNSTREAM PRESSURE HOSE CONNECTIONS Note • If the fault is currently present, DTC P1408 will be output in Key On Engine Running (KOER) self test. • Inspect downstream hose at D.P.F. EGR sensor and orifice tube assembly for disconnect or poor connection. • Is hose OFF or poorly connection?	Yes	Repair connections, then go to Step 25.
No	Go to the next step.
17	INSPECT DOWNSTREAM PRESSURE HOSE FOR PLUGGING Note • It is essential that the D.P.F. EGR sensor pressure hose is the correct repair part and not a substitute. • Visually inspect downstream pressure hose routing. Hose must not be pinched or have dips in it where water can settle or freeze. • Remove downstream pressure hose and carefully inspect for plugging, water or leaks. • Is there a fault detected the hose?	Yes	Repair or replace malfunctioning part, then go to Step 25.
No	Go to the next step.
18	CHECK ORIFICE TUBE ASSEMBLY AND D.P.F. EGR SENSOR • Inspect the connections at the D.P.F. EGR sensor for plugging or damage. • Inspect the intake manifold side pressure pickup tube and orifice tube assembly for plugging, loose connection or damage. • Is the D.P.F. EGR sensor or orifice tube assembly plugged, loose or damaged?	Yes	Repair or replace malfunctioning part, then go to the Step 25.
No	Go to the next step.
19	CHECK EGR SENSOR OUTPUT BY APPLYING VACUUM WITH HAND PUMP • Disconnect pressure hoses at D.P.F. EGR sensor. • Connect a hand vacuum to the downstream connection at sensor (intake manifold side of sensor or the smaller diameter pickup tube). • Turn the ignition switch to the ON position. • Access DPFEGR sensor PID and note PID value. • Apply 27—30 kPa {8—9 inHg} vacuum to the D.P.F. EGR sensor and hold for a few seconds. • Quickly release the vacuum. ― The DPFEGR PID voltage must be 0.2—1.3 V with the ignition switch ON and no vacuum applied. ― The DPFEGR PID voltage must increase to greater than 4.0 V with the vacuum applied. ― The DPFEGR PID must drop to less than 1.5 V in less than 3 seconds when vacuum is released. • Does the DPFEGR PID voltage indicate a fault in the D.P.F. EGR sensor?	Yes	Replace D.P.F. EGR sensor, then go to the Step 25.
No	Intermittent concern exists, go to Intermittent Troubleshooting Procedure. (See INTERMITTENT CONCERN TROUBLESHOOTING[AJ (3.0L Duratec)].)
20	INSPECT EGR SYTEM FOR AN INTERMITTENT FAILURE • Visually Inspect the EGR system for signs of intermittent failure. • Is a fault found?	Yes	Repair or replace malfunctioning part, then go to Step 25.
No	Go to the next step.
21	INSPECT D.P.F. EGR SENSOR PRESSURE HOSE • Visually inspect both pressure hoses for reversed connection at D.P.F. EGR sensor or at orifice tube assembly. • Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze. • Inspect both hoses for leaks and blockage. • Inspect D.P.F. EGR sensor and orifice tube assembly for blockage or damage at the pickup tubes. • Is a fault detected?	Yes	Repair or replace pressure hose, then go to Step 25.
No	Go to the next step.

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 P0401 on FREEZE FRAME DATA?

Yes

Go to the next step.

Go to FREEZE FRAME DATA DTC inspection.

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

RUN KEY ON ENGINE OFF (KOER) SELF TEST

• Perform the KOER self test.

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

• Is KOER DTC P1408 output?

Yes

Go to the next step.

Go to Step 10.

RETRIEVE CONTINUOUS MEMORY DTCS

Note

• If any DTC other than DTC P1406 is output, record DTC and refer to DTC table.

• Retrieve continuous memory DTCs.

• Is DTC P1406 displayed?

Yes

Go to Step 16.

Go to the next step.

RUN KOER SELF TEST WHILE MONITORING EGR VACUUM

• Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.

Note

• Since the EGR vacuum hose is disconnected, ignore DTCs during this KOER self test.

• Run KOER self test while monitoring gauge.

• Approximately 30 seconds into test, EGR flow will be requested for a few seconds.

• The vacuum at this time should increase above 5.4 kPa {1.6 inHg} to open the valve.

• Does the vacuum increase to 10 kPa {3.0 inHg} or greater at any time during KOER self test?

Yes

Go to the next step.

Go to Step 10.

INSPECT D.P.F. EGR SENSOR PRESSURE HOSES

• Visually inspect both pressure hoses for reserved connection at D.P.F. EGR sensor or at orifice tube assembly.

• Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze.

• Inspect D.P.F. EGR sensor and orifice tube assembly for blockage or damage at the pickup tubes.

• Is fault detected?

Yes

Repair pressure hose, then go to Step 25.

Go to the next step.

CHECK D.P.F. EGR SENSOR OUT PUT BY APPLYING VACUUM WITH HAND PUMP

• Connect the M-MDS to DLC-2.

• Disconnect pressure hoses at D.P.F. EGR sensor.

• Connect a hand vacuum pump to the downstream connection at sensor (intake manifold side of sensor or smaller diameter pickup tube.)

• Turn the ignition switch to the ON position.

• Disconnect pressure hoses at D.P.F. EGR sensor.

• Access DPFEGR PID and note PID value.

• Apply 27—30 kPa {8—9 inHg}vacuum to the D.P.F. EGR sensor and hold for a few seconds.

• Quickly release vacuum.

― The DPFEGR PID voltage must be between 0.2 and 1.3 V with the ignition switch ON and no vacuum applied.

― The DPFEGR PID voltage must increase to greater than 4.0 V with the vacuum applied.

― The DPFEGR PID must drop to less than 1.5 V in less than 3 seconds when vacuum is released.

• Does DPFEGR PID voltage indicate a fault in the D.P.F. EGR sensor?

Yes

Replace D.P.F. EGR sensor.

Go to the next step.

CHECK EGR VALVE FUNCTION BY APPLYING VACUUM WITH HAND PUMP

• Disconnect vacuum hose at EGR valve and plug hose.

• Connect a hand vacuum pump to EGR valve.

• Start the engine and bring to idle.

• Access DPSEGR and RPM PIDs.

• Slowly apply 27—34 kPa {210—250 mmHg, 8.0—10 inHg} vacuum to the D.P.F. EGR sensor and hold for 10 seconds. If engine want to stall increase engine speed with throttle to maintain a minimum of 1,000 rpm.

• Look for the following:

• Access DPFEGR and RPM PIDs.

― EGR valve starts opening at about 5.4 kPa {41 mmHg, 1.6 inHg} vacuum indicated by increasing D.P.F.EGR voltage.

― DPFEGR PID voltage increasing until EGR valve is fully open. DPFEGR PID must read 2.5 V minimum with full vacuum applied.

― DPFEGR PID voltage steady when vacuum is held. If voltage drops within a few seconds, the EGR valve or vacuum source can be leaking.

• Does the DPFEGR PID voltage indicate that the EGR valve is opening as described in this test?

Yes

Go to Step 15.

Remove and inspect the EGR valve for signs of contamination, unusual wear, carbon deposits, binding and other damage. If the EGR valve is normal, look for an obstruct EGR valve port in the intake manifold or plugged orifice tube assembly. Repair or replace malfunctioning part. Then go to Step 25.

CHECK VACUUM SOURCE AND VACUUM HOSES TO AND FROM EGR CONTROL VALVE

• Inspect vacuum lines between vacuum source and EGR control valve and between EGR control valve and EGR valve for leaks, kinks, disconnects, blockage, routing or any damage.

• Disconnect vacuum hoses at EGR control valve.

• Connect EGR control valve vacuum source hose to a vacuum gauge.

• With engine warm and at idle, take vacuum gauge reading.

• Is the vacuum gauge reading a minimum of 51 kPa {390 mmHg, 15 inHg} at idle and vacuum lines normal?

Yes

Go to the next step.

Isolate fault and repair or replace malfunctioning part, according to inspection result. Then go to Step 25.

CHECK PWR VOLTAGE TO EGR CONTROL VALVE

• Disconnect EGR control valve.

• Turn the ignition switch to the ON position.

• Measure voltage at EGR control valve terminal A and harness connector.

• Is the voltage greater than 10.5 V?

Yes

Go to the next step.

Repair or replace open circuit, then go to Step 25.

CHECK EGR CONTROL VALVE RESISTANCE

• Measure EGR control valve resistance.

• Is the resistance 26—40 ohms?

Yes

Go to the next step.

Replace EGR control valve, then go to Step 25.

CHECK EGR CONTROL VALVE CONTROL CIRCUIT SHORT TO POWER IN HARNESS

• Disconnect PCM.

• Turn the ignition switch to the ON position.

• Measure voltage between PCM harness side connector terminal 47 and battery negative post.

• Is voltage greater than 1.0 V?

Yes

Repair short circuit, then go to Step 25.

Go to the next step.

CHECK EGR CONTROL VALVE CIRCUIT FOR OPEN IN HARNESS

• Measure resistance of between EGR control valve terminal B and PCM terminal 47 at harness side connector.

• Is the resistance less than 5.0 ohms?

Yes

Go to the next step.

Repair open circuit, then go to Step 25.

CHECK EGR CONTROL VALVE VACUUM OUTPUT CAPABILITY BY GRIUNDUNG EGR CONTROL VALVE CONTROL CIRCUIT

• Disconnect vacuum hose at the EGR valve and connect to a vacuum gauge.

• Start the engine and run it at idle.

• With engine at idle, jumper PCM terminal 47 to chassis ground.

• Is vacuum gauge reading 13.5 kPa {110 mmHg, 4.0 inHg}?

Yes

Replace PCM, then go to Step 25.

Replace EGR control valve, then go to Step 25.

INPECT DOWNSTREAM PRESSURE HOSE CONNECTIONS

Note

• If the fault is currently present, DTC P1408 will be output in Key On Engine Running (KOER) self test.

• Inspect downstream hose at D.P.F. EGR sensor and orifice tube assembly for disconnect or poor connection.

• Is hose OFF or poorly connection?

Yes

Repair connections, then go to Step 25.

Go to the next step.

INSPECT DOWNSTREAM PRESSURE HOSE FOR PLUGGING

Note

• It is essential that the D.P.F. EGR sensor pressure hose is the correct repair part and not a substitute.

• Visually inspect downstream pressure hose routing. Hose must not be pinched or have dips in it where water can settle or freeze.

• Remove downstream pressure hose and carefully inspect for plugging, water or leaks.

• Is there a fault detected the hose?

Yes

Repair or replace malfunctioning part, then go to Step 25.

Go to the next step.

CHECK ORIFICE TUBE ASSEMBLY AND D.P.F. EGR SENSOR

• Inspect the connections at the D.P.F. EGR sensor for plugging or damage.

• Inspect the intake manifold side pressure pickup tube and orifice tube assembly for plugging, loose connection or damage.

• Is the D.P.F. EGR sensor or orifice tube assembly plugged, loose or damaged?

Yes

Repair or replace malfunctioning part, then go to the Step 25.

Go to the next step.

CHECK EGR SENSOR OUTPUT BY APPLYING VACUUM WITH HAND PUMP

• Disconnect pressure hoses at D.P.F. EGR sensor.

• Connect a hand vacuum to the downstream connection at sensor (intake manifold side of sensor or the smaller diameter pickup tube).

• Turn the ignition switch to the ON position.

• Access DPFEGR sensor PID and note PID value.

• Apply 27—30 kPa {8—9 inHg} vacuum to the D.P.F. EGR sensor and hold for a few seconds.

• Quickly release the vacuum.

― The DPFEGR PID voltage must be 0.2—1.3 V with the ignition switch ON and no vacuum applied.

― The DPFEGR PID voltage must increase to greater than 4.0 V with the vacuum applied.

― The DPFEGR PID must drop to less than 1.5 V in less than 3 seconds when vacuum is released.

• Does the DPFEGR PID voltage indicate a fault in the D.P.F. EGR sensor?

Yes

Replace D.P.F. EGR sensor, then go to the Step 25.

Intermittent concern exists, go to Intermittent Troubleshooting Procedure.

(See INTERMITTENT CONCERN TROUBLESHOOTING[AJ (3.0L Duratec)].)

INSPECT EGR SYTEM FOR AN INTERMITTENT FAILURE

• Visually Inspect the EGR system for signs of intermittent failure.

• Is a fault found?

Yes

Repair or replace malfunctioning part, then go to Step 25.

Go to the next step.

INSPECT D.P.F. EGR SENSOR PRESSURE HOSE

• Visually inspect both pressure hoses for reversed connection at D.P.F. EGR sensor or at orifice tube assembly.

• Inspect both hoses for improper routing. Hoses should not be pinched or have dips where water could settle or freeze.

• Inspect both hoses for leaks and blockage.

• Inspect D.P.F. EGR sensor and orifice tube assembly for blockage or damage at the pickup tubes.

• Is a fault detected?

Yes

Repair or replace pressure hose, then go to Step 25.

Go to the next step.