EGR problem
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EGR problem
Hi. I am new to the forum. I've replaced my EGR valve & sensor twice now within a year & half period. My check engine light is on again, & the codes indicate problems with the EGR vavle & sensor again. I've already replaced the valve, & I just bought a new sensor. Does anyone know if these things are suppose to wear out so soon? I'm starting to feel like these parts are like oil changes, & I have to change them every few thousand miles. It's getting very spendy, & I'm not happy. 
Post Fiend
Joined: Feb 2003
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From: Eastern WA
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Sorry. I was frustrated & forgot. It's a '98 ranger, 4cyl I think, 2wd. I don't remember the one code...but it was the insufficient flow thing. The other code was p1401 & it said manufacture auxillary emissions? The guy at Autozone didn't know what it meant, and the guy at the repair shop told me he couldn't tell me anything until he hooked it up (for $100) to get the code...even though I told him what the code was.
Post Fiend
Joined: Jan 2003
Posts: 9,748
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From: Connecticut
The components that you have replaced do not fail that often. My hunch is that your problem is in the circuitry somewhere. The "insuffufient flow" code is probably a P0401 code. That code alone would normally indicate a clogged EGR valve/tube or a failed DPFE sensor. But the additional P01401 suggests that the reason for the insufficient flow is that the circuit is not operating properly and hence not allowing the components to do their job(s). In fact, the possible causes that the Ford Manual sets forth for the P0401 are more or less all related to the circuitry:
- DPF EGR circuit open
- VREF short to PWR
- Damaged DPF EGR sensor
- DPFEGR circuit short to PWR
- SIG RTN circuit open
- Damaged PCM
So I think it's time for someone to break out the multimeter and do some electrical testing.
Here are few links that might help you figure some things out:
Ford DPFE/EGR System Summary
Troubleshooting the Ford DPFE/EGR System (PDF)
- DPF EGR circuit open
- VREF short to PWR
- Damaged DPF EGR sensor
- DPFEGR circuit short to PWR
- SIG RTN circuit open
- Damaged PCM
So I think it's time for someone to break out the multimeter and do some electrical testing.
Here are few links that might help you figure some things out:Ford DPFE/EGR System Summary
Troubleshooting the Ford DPFE/EGR System (PDF)
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Well, I guess that means I've got to bite the bullet & pay the $100 to have the repair shop tell me the exact problem, unless someone has a better idea. Do you think that I should put off replacing the DPFE & get it diagnosed first?
Post Fiend
Joined: Jan 2003
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From: Connecticut
Since you have replaced the DPFE sensor twice within the past 1.5 years, then I'd hold off on a new one and apply the funds toward a professional diagnosis.
In the meantime, check the harness connector to the DPFE sensor, see if any of wires are cut or chafed, look for any kind of area where the wiring might be rubbing against something, etc.
In the meantime, check the harness connector to the DPFE sensor, see if any of wires are cut or chafed, look for any kind of area where the wiring might be rubbing against something, etc.
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From: Rocky Mountains
A visual inspection of the EGR system is very important. I fought a similar problem for some time before I found a cracked hose going to the EVR solenoid. So if you haven't replaced the hoses in the EGR system, it's a cheap first step.
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A vacume leake wille make the egr systeme reade bade tooe. I have also reade of meny cases of clogged egr systemes being causede by running higher octane gass. next fill up, use low grade gas, put some injektor cleenor in your tank. Disconnect the battere to clear the code, and run it like you bought it from your brother.
I typed that irritating crap on purpose.
I typed that irritating crap on purpose.
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Ok. SO I took it to a shop & thought they were going to tell me exactly what the problem is. Instead, they told me that the code is p1401 (which I knew alread) & it said sensor circuit high voltage detected. Anybody knows what that could mean? They said it would cost me $350 for them to tell me the exact issue.
Post Fiend
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From: South Jersey
Diagnostic Trouble Code (DTC) P1401 indicates that Self-Test has detected DPFEGR circuit input above the maximum.
Possible causes:
DPFEGR open.
DPFEGR shorted to VREF or PWR.
VREF shorted to PWR.
SIG RTN open.
Damaged D.P.F. EGR sensor.
Damaged PCM.
Sounds like wiring since you replaced the DPFE sensor.
Possible causes:
DPFEGR open.
DPFEGR shorted to VREF or PWR.
VREF shorted to PWR.
SIG RTN open.
Damaged D.P.F. EGR sensor.
Damaged PCM.
Sounds like wiring since you replaced the DPFE sensor.
Post Fiend
Joined: Dec 2001
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From: South Jersey
HE10 MEASURE VREF CIRCUIT VOLTAGE AT FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION SENSOR
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Key on, engine off.
l Measure voltage between VREF circuit and SIG RTN circuit at the Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor vehicle harness connector.
l Is voltage between 4.0 and 6.0 volts?
Yes
GO to «HE11».
No
REPAIR VREF circuit. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE11 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT CONTINUITY
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Leave PCM disconnected.
l Measure resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position circuit at the appropriate sensor vehicle harness connector and the corresponding circuit at the breakout box.
l Is resistance less than 5.0 ohms?
Yes
GO to «HE12».
No
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE12 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT FOR SHORTS TO GROUND
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Breakout box installed, PCM disconnected.
l EGRT sensor disconnected, if applicable.
l Measure resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor and PWR GND at the breakout box.
l Is each resistance greater than 10,000 ohms?
Yes
GO to «HE13».
No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE13 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT FOR SHORTS TO POWER
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Measure the resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor and VPWR at the breakout box.
l Is each resistance greater than 10,000 ohms?
Yes
For Feedback Pressure EGR/Differential Pressure Feedback EGR:
GO to «HE15».
For EGR Valve Position:
GO to «HE17».
No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE14 BVT CHECK
l Reconnect the idle air bypass valve electrical connector.
l Unplug and reconnect the EGR vacuum supply hose.
l Disconnect the vacuum line of the BVT.
l Apply 17-34 kPa (5-10 in-Hg) vacuum to Ports B and C using a hand vacuum pump. Ports B and C should hold vacuum.
l Gently blow into the hose to Port C until the relief valve closes and at the same time apply 17-34 kPa (5-10 in-Hg) vacuum to Port E with a hand vacuum pump. Port E should hold vacuum as long as there is pressure on Port C.
l Does BVT hold vacuum?
Yes
BVT is OK. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
REPLACE BVT. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE15 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR SENSOR PRESSURE INPUT HOSE(S)
l Remove each pressure input hose from Feedback Pressure EGR/Differential Pressure Feedback EGR sensor.
l Inspect each hose and Feedback Pressure EGR/Differential Pressure Feedback EGR sensor inlet(s) for blockage or leaks.
l Is blockage or leak present?
Yes
SERVICE as necessary. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
RECONNECT pressure input hose(s). GO to «HE16».
HE16 CHECK FOR EXHAUST RESTRICTION
l Attach vacuum gauge to intake manifold source.
l Hook up tachometer.
l NOTE:
On a non-restricted system, the vacuum gauge needle will drop to zero and then quickly return to normal (above 54 kPa (16 in-Hg)). On a restricted system, the vacuum gauge needle will slowly drop to zero and slowly increase as rpm is maintained. The rate of speed at which the vacuum gauge needle returns to normal is much slower on a restricted system.
Observe the vacuum gauge needle while performing the following:
-- Start engine and gradually increase the rpm from base idle to 2000 rpm with the transmission in NEUTRAL.
-- Observe the rate of speed of the vacuum gauge needle as it falls and rises while maintaining the increased engine rpm and also note final vacuum reading.
l Does the vacuum gauge needle return to normal quickly, and is a (minimum) vacuum of 54 kPa (16 in-Hg) reached?
Yes
No restriction in the exhaust system. GO to «HE17».
No
GO to «HF1» in Section 5, Catalyst and Exhaust Systems, for further diagnosis
HE17 CHECK FOR INTERMITTENT SENSOR
l Connect voltmeter between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position and SIG RTN pins at the breakout box.
l Key on, engine off.
l NOTE:
EGR valve position circuit voltage with EGR valve closed is normally between 0.24 and 0.67 volt and steady. A sudden change in voltage indicates a fault.
Lightly tap on EGR valve position sensor and wiggle harness connector to simulate road shock.
l Is a fault indicated?
Yes
REMOVE and INSPECT EGR valve position sensor connector. If OK, REPLACE EVP sensor. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
LEAVE voltmeter connected, RECONNECT PCM and GO to «HE18».
HE18 CHECK VOLTAGE WHILE EXERCISING EGR VALVE
l Disconnect vacuum hose at EGR valve and connect a vacuum pump.
l Key on, engine off.
l Measure voltage between EGR valve position and SIG RTN at the breakout box while performing the following:
-- Slowly apply 5 - 10 in-Hg (17-34 kPa) of vacuum to EGR valve then slowly bleed vacuum.
l Does the voltage increase and decrease steadily from no more than 4.81 volts to no less than 0.24 volt?
Yes
Go to «HE19».
No
REPLACE EGR valve position sensor. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE19 WIGGLE TEST SENSOR
l Enter Engine Running Continuous Monitor DTM (refer to Quick Test Appendix, «Section 2»).
l Observe voltmeter or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
-- Lightly tap on Feedback Pressure EGR/Differential Pressure Feedback EGR sensor and wiggle the sensor vehicle harness connector (to simulate road shock).
l Is a fault indicated?
Yes
INSPECT connectors and terminals, If OK, replace Feedback Pressure EGR/Differential Pressure Feedback EGR sensor, RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
GO to «HE20».
HE20 WIGGLE TEST EEC-IV VEHICLE HARNESS
l Still in Engine Running Continuous Monitor DTM.
l Observe DVOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
-- Grasp the vehicle harness closest to the EVP/PFE/DPFE sensor connector. Wiggle, shake or bend a small section of the EEC-IV system vehicle harness while working toward the dash panel. Also, wiggle, shake or bend the EEC-IV vehicle harness from the dash panel to the PCM.
l Is a fault indicated?
Yes
ISOLATE fault and SERVICE as necessary. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
GO to «HE22».
HE22 CHECK SOLENOID FOR INTERMITTENT SHORTS
l An EVR solenoid or EVR driver circuit short could cause the EVR to open supplying the EGR valve with vacuum.
l Key off.
l Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
l Run engine to operating temperature and stabilized idle.
l With the engine at idle, tap the EVR solenoid and wiggle the EVR connector while noting vacuum reading.
NOTE:
EVR leakage below 3.4 kPa (1.0 in-Hg) is normal.
l Does the EGR vacuum remain below 3.4 kPa (1.0 In-Hg) with no sudden increase?
Yes
LEAVE vacuum gauge connected.
GO to «HE23».
No
INSPECT EVR solenoid connector for shorts. SERVICE as necessary. If OK, SERVICE or REPLACE solenoid(s). RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE23 CHECK HARNESS CIRCUIT FOR INTERMITTENT BETWEEN SOLENOID(S) AND PCM
l Vacuum gauge connected.
l Key on, engine running.
l Look for an increase in EGR vacuum while performing the following:
-- With the engine at idle, wiggle the solenoid harness between the solenoid(s) and dash panel and between dash panel and Powertrain Control Module (PCM).
l Does the EGR vacuum increase?
Yes
ISOLATE and SERVICE short in solenoid circuit. REMOVE vacuum gauge. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
Unable to identify fault at this time. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Key on, engine off.
l Measure voltage between VREF circuit and SIG RTN circuit at the Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor vehicle harness connector.
l Is voltage between 4.0 and 6.0 volts?
Yes
GO to «HE11».
No
REPAIR VREF circuit. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE11 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT CONTINUITY
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Leave PCM disconnected.
l Measure resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position circuit at the appropriate sensor vehicle harness connector and the corresponding circuit at the breakout box.
l Is resistance less than 5.0 ohms?
Yes
GO to «HE12».
No
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE12 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT FOR SHORTS TO GROUND
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Breakout box installed, PCM disconnected.
l EGRT sensor disconnected, if applicable.
l Measure resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor and PWR GND at the breakout box.
l Is each resistance greater than 10,000 ohms?
Yes
GO to «HE13».
No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE13 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR/EGR VALVE POSITION CIRCUIT FOR SHORTS TO POWER
l Key off.
l Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor disconnected.
l Measure the resistance between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position sensor and VPWR at the breakout box.
l Is each resistance greater than 10,000 ohms?
Yes
For Feedback Pressure EGR/Differential Pressure Feedback EGR:
GO to «HE15».
For EGR Valve Position:
GO to «HE17».
No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE14 BVT CHECK
l Reconnect the idle air bypass valve electrical connector.
l Unplug and reconnect the EGR vacuum supply hose.
l Disconnect the vacuum line of the BVT.
l Apply 17-34 kPa (5-10 in-Hg) vacuum to Ports B and C using a hand vacuum pump. Ports B and C should hold vacuum.
l Gently blow into the hose to Port C until the relief valve closes and at the same time apply 17-34 kPa (5-10 in-Hg) vacuum to Port E with a hand vacuum pump. Port E should hold vacuum as long as there is pressure on Port C.
l Does BVT hold vacuum?
Yes
BVT is OK. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
REPLACE BVT. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE15 CHECK FEEDBACK PRESSURE EGR/DIFFERENTIAL PRESSURE FEEDBACK EGR SENSOR PRESSURE INPUT HOSE(S)
l Remove each pressure input hose from Feedback Pressure EGR/Differential Pressure Feedback EGR sensor.
l Inspect each hose and Feedback Pressure EGR/Differential Pressure Feedback EGR sensor inlet(s) for blockage or leaks.
l Is blockage or leak present?
Yes
SERVICE as necessary. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
RECONNECT pressure input hose(s). GO to «HE16».
HE16 CHECK FOR EXHAUST RESTRICTION
l Attach vacuum gauge to intake manifold source.
l Hook up tachometer.
l NOTE:
On a non-restricted system, the vacuum gauge needle will drop to zero and then quickly return to normal (above 54 kPa (16 in-Hg)). On a restricted system, the vacuum gauge needle will slowly drop to zero and slowly increase as rpm is maintained. The rate of speed at which the vacuum gauge needle returns to normal is much slower on a restricted system.
Observe the vacuum gauge needle while performing the following:
-- Start engine and gradually increase the rpm from base idle to 2000 rpm with the transmission in NEUTRAL.
-- Observe the rate of speed of the vacuum gauge needle as it falls and rises while maintaining the increased engine rpm and also note final vacuum reading.
l Does the vacuum gauge needle return to normal quickly, and is a (minimum) vacuum of 54 kPa (16 in-Hg) reached?
Yes
No restriction in the exhaust system. GO to «HE17».
No
GO to «HF1» in Section 5, Catalyst and Exhaust Systems, for further diagnosis
HE17 CHECK FOR INTERMITTENT SENSOR
l Connect voltmeter between Feedback Pressure EGR/Differential Pressure Feedback EGR/EGR Valve Position and SIG RTN pins at the breakout box.
l Key on, engine off.
l NOTE:
EGR valve position circuit voltage with EGR valve closed is normally between 0.24 and 0.67 volt and steady. A sudden change in voltage indicates a fault.
Lightly tap on EGR valve position sensor and wiggle harness connector to simulate road shock.
l Is a fault indicated?
Yes
REMOVE and INSPECT EGR valve position sensor connector. If OK, REPLACE EVP sensor. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
LEAVE voltmeter connected, RECONNECT PCM and GO to «HE18».
HE18 CHECK VOLTAGE WHILE EXERCISING EGR VALVE
l Disconnect vacuum hose at EGR valve and connect a vacuum pump.
l Key on, engine off.
l Measure voltage between EGR valve position and SIG RTN at the breakout box while performing the following:
-- Slowly apply 5 - 10 in-Hg (17-34 kPa) of vacuum to EGR valve then slowly bleed vacuum.
l Does the voltage increase and decrease steadily from no more than 4.81 volts to no less than 0.24 volt?
Yes
Go to «HE19».
No
REPLACE EGR valve position sensor. REMOVE breakout box. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE19 WIGGLE TEST SENSOR
l Enter Engine Running Continuous Monitor DTM (refer to Quick Test Appendix, «Section 2»).
l Observe voltmeter or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
-- Lightly tap on Feedback Pressure EGR/Differential Pressure Feedback EGR sensor and wiggle the sensor vehicle harness connector (to simulate road shock).
l Is a fault indicated?
Yes
INSPECT connectors and terminals, If OK, replace Feedback Pressure EGR/Differential Pressure Feedback EGR sensor, RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
GO to «HE20».
HE20 WIGGLE TEST EEC-IV VEHICLE HARNESS
l Still in Engine Running Continuous Monitor DTM.
l Observe DVOM or listen for beeper to sound on Super Star II for indication of a fault while performing the following:
-- Grasp the vehicle harness closest to the EVP/PFE/DPFE sensor connector. Wiggle, shake or bend a small section of the EEC-IV system vehicle harness while working toward the dash panel. Also, wiggle, shake or bend the EEC-IV vehicle harness from the dash panel to the PCM.
l Is a fault indicated?
Yes
ISOLATE fault and SERVICE as necessary. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
GO to «HE22».
HE22 CHECK SOLENOID FOR INTERMITTENT SHORTS
l An EVR solenoid or EVR driver circuit short could cause the EVR to open supplying the EGR valve with vacuum.
l Key off.
l Disconnect vacuum hose at EGR valve and connect hose to a vacuum gauge.
l Run engine to operating temperature and stabilized idle.
l With the engine at idle, tap the EVR solenoid and wiggle the EVR connector while noting vacuum reading.
NOTE:
EVR leakage below 3.4 kPa (1.0 in-Hg) is normal.
l Does the EGR vacuum remain below 3.4 kPa (1.0 In-Hg) with no sudden increase?
Yes
LEAVE vacuum gauge connected.
GO to «HE23».
No
INSPECT EVR solenoid connector for shorts. SERVICE as necessary. If OK, SERVICE or REPLACE solenoid(s). RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
HE23 CHECK HARNESS CIRCUIT FOR INTERMITTENT BETWEEN SOLENOID(S) AND PCM
l Vacuum gauge connected.
l Key on, engine running.
l Look for an increase in EGR vacuum while performing the following:
-- With the engine at idle, wiggle the solenoid harness between the solenoid(s) and dash panel and between dash panel and Powertrain Control Module (PCM).
l Does the EGR vacuum increase?
Yes
ISOLATE and SERVICE short in solenoid circuit. REMOVE vacuum gauge. RECONNECT all components. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.
No
Unable to identify fault at this time. RETURN to the Test Step in «Section 3», Symptom Charts, which sent you to this Pinpoint Test.