Question about 1995 Geo Prizm

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1996 Goe Prizm 1.6 P401

96 Geo P401 (insufficient flow detected). No ground signal at egr solenoid in drive while power braking. Does not stall with egr removed. There is vacuum at intake port when egr is removed. With direct vacuum to egr code P401 still sets. Engine temp warmed up is 190 degrees. Thanks Peter

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My first car was a 69 dart with 340 hi pro 4 speed bad *** car

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Why is codes p2106 p0401 on?


P2106 THROTTLE ACTUATOR CONTROL SYSTEM,-PO401-EGR INSUFFICIENT FLOW

May 29, 2014 | 2005 Ford Explorer

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I replaced the EGR valve on the car and now have an error code indicating "EGR valve insufficient air flow..." I cleaned out a lot of carbon and junk that I could reach with a short piece of wire...


The air flow through the EGR is usually detected by a DPFE (differential Pressure Feedback Exhaust) sensor. The DPFE is connected by two pipes/ports on the exhaust feed pipe leading to the EGR. This sensor measures the pressure difference (differential) in the two pipes when the EGR is open; the more open the EGR the more the pressure imbalance detected by the DPFE. If the pipes/ports to the DPFE become clogged or the sensor malfunctions, the signal to the ECU will be seen as incorrect as compared to how much the EGR has opened...'insufficient air flow'. It is just as likely for the DPFE to fail as the EGR when there are 'EGR problems' . Hope this gives you another thing to check

Sep 21, 2011 | 1996 Geo Prizm

1 Answer

I have an 04 Kia spectra with a PO121 code. What domestic this mean


Well.... Here is a full list of the codes I can find that Kia list. Oddly it jumps from P0120 to P0122

I hope the attached will help, but you may need to talk to your dealer.


Diagnostic Codes
Kia
Without Onboard Diagnostics (OBD-II)
2 Distributor no Signal.
3 Distributor G Signal.
7 Fault on SGT Signal.
8 Mass Air Flow Sensor.
9 Engine Coolant Temperature Sensor.
10 Intake Air Temperature Sensor.
12 Throttle Position Sensor.
14 Atmospheric Pressure Sensor.
15 Oxygen Sensor.
16 EGR Valve Position Sensor.
17 Feedback System.
18 Injector No. 1 open or short.
19 Injector No. 2 open or short.
20 Injector No. 3 open or short.
21 Injector No. 4 open or short.
24 Fuel Pump Relay open or short.
25 Pressure Regulator Control Solenoid Valve.
26 Purge Control Solenoid Valve.
28 Solenoid Valve (EGR) open or short.
34 Idle Speed Control Solenoid Valve.
35 Deteriorated Injector.
36 Deteriorated Air Flow Sensor.
37 Intake System Air Leakage.
41 Variable Inertia Charging System Solenoid Valve.
46 A/C Cut Relay open or short.
48 Power Stage Group 1 Malfunction (inside ECM). Injector 1-4 Purge Solenoid Valve, EGR Solenoid Valve or Damaged Power Stage.
49 Power Stage Group 2 Malfunction (inside ECM). Idle Speed Control Valve Failure or Damaged Power Stage.
56 Idle Speed Control Valve Closing Coil open or short.
57 A/C Compressor Input Signal short.
73 Vehicle Speed Sensor open or short.
87 Malfunction Indicator Lamp short Circuit.
88 ECM Data.
99 Battery.





OBD-II

P0100 Mass Air Flow or Volume Air Flow Circuit Malfunction.
P0101 Mass Air Flow or Volume Air Flow Circuit Range/Performance problem.
P0102 Mass Air Flow or Volume Air Flow Circuit Low Input.
P0103 Mass Air Flow or Volume Air Flow Circuit High Input.
P0107 MAP/BARO Circuit Low Input.
P0108 MAP/BARO Circuit High Input.
P0110 A/T Circuit Malfunction.
P0115 Engine Coolant Temperature Circuit Malfunction.
P0116 Engine Coolant Temperature Circuit Range/Performance Condition.
P0117 Engine Coolant Temperature Circuit Low Input.
P0118 Engine Coolant Temperature Circuit High Input.
P0120 Throttle Position Malfunction - Circuit A.
P0122 APP/TPP Sensor Switch Low Input - Circuit A.
P0123 APP/TPP Sensor Switch High Input - Circuit A.
P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control.
P0130 Oxygen Sensor Circuit Malfunction - Bank 1 Sensor 1.
P0131 Oxygen Sensor Circuit Low Voltage - Bank 1 Sensor 1.
P0132 Oxygen Sensor Circuit High Voltage - Bank 1 Sensor 1.
P0133 Oxygen Sensor Circuit Slow Response - Bank 1 Sensor 1.
P0134 Oxygen Sensor Circuit No Activity detected - Bank 1 Sensor 1.
P0135 Oxygen Sensor Heater Circuit Malfunction - Bank 1 Sensor 1.
P0136 Oxygen Sensor Circuit Malfunction - Bank 1 Sensor 2.
P0137 Oxygen Sensor Circuit Low Voltage - Bank 1 Sensor 2.
P0138 Oxygen Sensor Circuit High Voltage - Bank 1 Sensor 2.
P0139 Oxygen Sensor Circuit Slow Response - Bank 1 Sensor 2.
P0140 Oxygen Sensor Circuit No Activity detected - Bank 1 Sensor 2.
P0141 Oxygen Sensor Heater Circuit Malfunction - Bank 1 Sensor 2.
P0170 Fuel Trim Malfunction - Bank 1.
P0171 System too Lean - Bank 1.
P0172 System too Rich - Bank 1.
P0261 Injector Circuit Low - Cyl. 1.
P0262 Injector Circuit High - Cyl. 1.
P0264 Injector Circuit Low - Cyl. 2.
P0265 Injector Circuit High - Cyl. 2.
P0267 Injector Circuit Low - Cyl. 3.
P0268 Injector Circuit High - Cyl. 3.
P0270 Injector Circuit Low - Cyl. 4.
P0271 Injector Circuit High - Cyl. 4.
P0300 Multiple/Random Misfire detected.
P0301 Misfire detected - Cyls. 1-4.
P0302 Misfire detected - Cyls. 1-4.
P0303 Misfire detected - Cyls. 1-4.
P0304 Misfire detected - Cyls. 1-4.
P0325 Knock Sensor Circuit Malfunction
P0326 Knock Sensor 1 Circuit Range/Performance - Bank 1 or Single Sensor.
P0335 Crankshaft Position Sensor Malfunction - Circuit A.
P0336 Crankshaft Position Sensor Range/Performance - Circuit A.
P0340 Crankshaft Position Sensor Circuit Malfunction.
P0342 Crankshaft Position Sensor Circuit Low Input.
P0343 Crankshaft Position Sensor Circuit High Input.
P0400 EGR Flow Malfunction.
P0403 EGR Circuit Malfunction.
P0404 EGR Circuit Range/Performance Malfunction.
P0420 Catalyst System Efficiency below Threshold - Bank 1.
P0422 Main Catalyst Efficiency below Threshold - Bank 1.
P0440 Evaporative Control Malfunction.
P0441 Evaporative Control System - Improper Purge.
P0442 Evaporative Control System - Small Leak detected.
P0443 Evaporative Control System Purge Control Valve Circuit Malfunction.
P0446 Evaporative Vent Control Circuit Malfunction.
P0447 Evaporative Vent Control Circuit Open.
P0448 Evaporative Vent Control Circuit Short.
P0450 Evaporative System Pressure Sensor Circuit Malfunction.
P0452 Evaporative Control System Pressure Sensor Low Input.
P0453 Evaporative Control System Pressure Sensor High Input.
P0455 Evaporative Control System - Large Leak detected.
P0470 Exhaust Pressure Sensor Malfunction.
P0500 Vehicle Speed Sensor Malfunction.
P0501 Vehicle Speed Sensor Range/Performance.
P0505 Idle Air Control System Malfunction.
P0506 Idle Air Control System Malfunction - RPM Lower than expected.
P0507 Idle Air Control System Malfunction - RPM Higher than expected.
P0510 CTP Switch Malfunction.
P0561 System Voltage Unstable.
P0562 System Voltage Low.
P0563 System Voltage High.
P0601 Internal Control Module Memory Checksum Error.
P0604 Internal Control Module RAM Error.
P0703 Torque Converter/Brake Pedal Switch Malfunction - Circuit B.
P0705 Transaxle Range Sensor Circuit Malfunction (PRNDL Input).
P0706 A/T Range Sensor Circuit Range/ Performance.
P0710 Transaxle Fluid Temperature Sensor Circuit Malfunction.
P0711 A/T Fluid Temperature Sensor Circuit Range/Performance.
P0715 Input/Turbine Speed Sensor Circuit Malfunction.
P0722 Output Speed Sensor Circuit No Signal.
P0726 Engine Speed Input Circuit Range/ Performance.
P0727 Engine Speed Input Circuit - No Signal.
P0731 A/T Gear 1 Improper Ratio.
P0732 A/T Gear 2 Improper Ratio.
P0733 A/T Gear 3 Improper Ratio.
P0734 A/T Gear 4 Improper Ratio.
P0740 Torque Converter Clutch System Malfunction.
P0743 Torque Converter Clutch Circuit Electrical.
P0750 Shift Solenoid "A" Malfunction.
P0753 Shift Solenoid "A" Electrical.
P0755 Shift Solenoid "B" Malfunction.
P0758 Shift Solenoid "B" Electrical.
P0760 Shift Solenoid "C" Malfunction.
P1000 Readiness Function Code.
P1115 Engine Coolant Temperature Signal from ECM to TCM.
P1121 Throttle Position Sensor Signal Malfunction from ECM to TCM.
P1170 Front Heated Oxygen Sensor Stuck.
P1195 EGR Pressure Sensor (1.6L) or Boost Sensor (1.8L) Open or Short.
P1196 Ignition Switch "Start" Open or Short (1.6L).
P1250 Pressure Regulator Control Solenoid Valve Open or Short.
P1252 Pressure Regulator Control Solenoid Valve No. 2 Circuit Malfunction.
P1307 Chassis Acceleration Sensor Signal Malfunction.
P1308 Chassis Acceleration Sensor Signal Low.
P1309 Chassis Acceleration Sensor Signal High.
P1345 No SGC Signal (1.6L).
P1386 Knock Sensor Control Zero Test.
P1402 EGR Valve Position Sensor Open or Short.
P1449 Canister Drain Cut Valve Open or Short (1.8L).
P1450 Excessive Vacuum Leak.
P1455 Fuel Tank Sending Unit Open or Short (1.8L).
P1457 Purge Solenoid Valve Low System Malfunction.
P1458 A/C Compressor Control Signal Malfunction.
P1485 EGR Solenoid Valve Vacuum Open or Short.
P1486 EGR Solenoid Valve Vent Open or Short.
P1487 EGR Boost Sensor Solenoid Valve Open or Short.
P1496 EGR Stepper Motor Malfunction - Circuit 1 (1.8L).
P1497 EGR Stepper Motor Malfunction - Circuit 2 (1.8L).
P1498 EGR Stepper Motor Malfunction - Circuit 3 (1.8L).
P1499 EGR Stepper Motor Malfunction - Circuit 4 (1.8L).
P1500 No Vehicle Speed Signal to TCM.
P1505 Idle Air Control Valve Opening Coil Voltage Low.
P1506 Idle Air Control Valve Opening Coil Voltage High.
P1507 Idle Air Control Valve Closing Coil Voltage Low.
P1508 Idle Air Control Valve Closing Coil Voltage High.
P1523 VICS Solenoid Valve.
P1586 A/T-M/T Codification.
P1608 PCM Malfunction.
P1611 MIL Request Circuit Voltage Low.
P1614 MIL Request Circuit Voltage High.
P1624 MIL Request Signal from TCM to ECM.
P1631 Alternator "T" Open or No Power Output (1.8L).
P1632 Battery Voltage Detection Circuit for Alternator Regulator (1.8L).
P1633 Battery Overcharge.
P1634 Alternator "B" Open (1.8L).
P1693 MIL Circuit Malfunction.
P1743 Torque Converter Clutch Solenoid Valve Open or Short.
P1794 Battery or Circuit Failure.
P1795 4WD Switch Signal Malfunction.
P1797 P or N Range Signal or Clutch Pedal Position Switch Open or Short.

Jun 21, 2011 | 2004 Kia Spectra

3 Answers

EGR flow in our 2000 Ford Expedition is insufficient. What does this mean?


Exhaust gas recirculation flow reduced. Could be caused by valve or gunk in the flow path. I'll paste a little bit about troubleshooting below. If you need specific instructions for repairing your system, please reply with your engine size/type.

The Exhaust Gas Recirculation (EGR) system is designed to reintroduce exhaust gas into the combustion chambers, thereby lowering combustion temperatures and reducing the formation of Oxides of Nitrogen (NO x ).
The amount of exhaust gas that is reintroduced into the combustion cycle is determined by several factors, such as: engine speed, engine vacuum, exhaust system backpressure, coolant temperature, throttle position. All EGR valves are vacuum operated. The EGR vacuum diagram for your particular vehicle is displayed on the Vehicle Emission Control Information (VECI) label.
The EGR system is Differential Pressure Feedback EGR (DPFE) system, controlled by the Powertrain Control Module (PCM) and composed of the following components: DPFE sensor (also referred to as the backpressure transducer), EGR Vacuum Regulator (EVR) solenoid, EGR valve, and assorted hoses.


COMPONENT TESTING

DPFE Sensor

  1. Disconnect the pressure hoses at the DPFE sensor.
  2. Connect a hand vacuum pump to the downstream pickup marked REF on the sensor.
  3. Using a multimeter, backprobe the SIG RTN circuit at the DPFE connector.
  4. With the ignition ON , signal voltage should be 0.20-0.70 volts.
  5. Apply 8-9 in. Hg of vacuum to the sensor. Voltage should be greater than 4 volts.
  6. Quickly release the vacuum from the sensor. Voltage should drop to less than 1 volt in 3 seconds.
  7. If the sensor does not respond as specified, check the power and ground circuits.
  8. If power and ground circuits are functional, the sensor is faulty.

EGR Valve Control Solenoid
  1. Remove the EVR solenoid.
  2. Attempt to lightly blow air into the EVR solenoid.
    1. If air blows through the solenoid, replace the solenoid with a new one.
    2. If air does not pass freely through the solenoid, continue with the test.

  3. Apply battery voltage (approximately 12 volts) and a ground to the EVR solenoid electrical terminals. Attempt to lightly blow air, once again, through the solenoid.
    1. If air does not pass through the solenoid, replace the solenoid with a new one.
    2. If air does not flow through the solenoid, the solenoid is OK.

  4. If the solenoid is functional but the problem still exists, check the power and ground circuits.

EGR Valve
  1. Install a tachometer on the engine, following the manufacturer's instructions.
  2. Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
  3. Disconnect and plug the vacuum supply hose from the EGR valve.
  4. Start the engine, then apply the parking brake, block the rear wheels and position the transmission in Neutral.
  5. Observe and note the idle speed.

If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.
  1. Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple.
    1. If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
    2. If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.

Sep 27, 2010 | 2000 Ford Expedition

1 Answer

Exhaust Gas Recirculation Flow Insufficient Detected 2002 Ford Crown Victoria LX The car works very good at 60 and I go 35 to city and then when we slow down to city speeds it will have little jerks and we...


P0401 - EGR Flow Insufficient Detected The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.
  • Vacuum supply
  • EGR valve stuck closed
  • EGR valve leaks vacuum
  • EGR flow path restricted
  • EGRVR circuit shorted to PWR
  • VREF open to D.P.F. EGR sensor
  • D.P.F. EGR sensor downstream hose off or plugged
  • EGRVR circuit open to PCM
  • VPWR open to EGRVR solenoid
  • D.P.F. EGR sensor hoses both off
  • D.P.F. EGR sensor hoses reversed
  • Damaged EGR orifice tube
  • Damaged EGRVR solenoid
  • Damaged PCM
Perform KOER self-test and look for DTC P1408 as an indication of a hard fault. If P1408 is not present, look for contamination, restrictions, leaks, and intermittents.
not likely the PCM, engine computer. they seldom go bad.
report back findings.

May 16, 2010 | 2002 Ford Crown Victoria

1 Answer

What's wrong with the code P0401 for camry 96


P0401 OBD-II Trouble Code
Insufficient EGR Flow
What does that mean?
EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor (DPF). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.

May 06, 2010 | 1996 Toyota Camry

1 Answer

1996 ford windstar 3.8 codes say that cylinders 4 and 6 are misfiring,system too lean bank 1,egr flow insufficient. whats up?


Cylinder misfiring hapens when ignition coil is bad and bad spark plugs.
System to lean is usualy when fuel pump lose pressure or you have blown gasket on intake manifold. Check fuel pressure first.
When EGR flow is insufficient there is EGR valve, sensor and solenoid, could go bad., so you have multiple codes P0171, P0304,P0306, P0401

Feb 21, 2010 | 1996 Ford Windstar

1 Answer

99 5.4 Expedition issues


P0401 - EGR Flow Insufficient Detected The EGR system is monitored during steady state driving conditions while the EGR is commanded on. The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum.
  • Vacuum supply
  • EGR valve stuck closed
  • EGR valve leaks vacuum
  • EGR flow path restricted
  • EGRVR circuit shorted to PWR
  • VREF open to DPF EGR sensor
  • DPF EGR sensor downstream hose off or plugged
  • EGRVR circuit open to PCM
  • VPWR open to EGRVR solenoid
  • DPF EGR sensor hoses both off
  • DPF EGR sensor hoses reversed
  • Damaged EGR orifice tube
  • Damaged EGRVR solenoid
  • Damaged PCM

P1299 - Cylinder Head Over Temperature Protection Active Indicates an engine overheat condition was detected by the cylinder head temperature (CHT) sensor. An FMEM Strategy called Fail-safe Cooling was activated to cool the engine.
  • Engine cooling system concerns
  • Low engine coolant level
  • Base engine concerns

P0300 - Random Misfire The random misfire DTC indicates multiple cylinders are misfiring or the PCM cannot identify which cylinder is misfiring.
  • Camshaft position sensor (CMP)
  • Low fuel: less than 1/8 tank
  • Stuck open EGR valve

P0443 - EVAP Control System Canister Purge Valve Circuit Malfunction The PCM monitors the EVAP canister purge valve circuit for an electrical failure. The test fails when the signal moves outside the minimum or maximum allowable calibrated parameters for a specified purge duty cycle by PCM command.
  • VPWR circuit open
  • EVAP canister purge valve circuit shorted to GND
  • Damaged EVAP canister purge valve
  • EVAP canister purge valve circuit open
  • EVAP canister purge valve circuit shorted to VPWR
  • Damaged PCM

P1451 - EVAP Control System Canister Vent Solenoid Circuit Malfunction Monitors the canister vent (CV) solenoid circuit for an electrical failure. The test fails when the signal moves outside the minimum or maximum allowable calibrated parameters for a specified canister vent duty cycle by PCM command.
  • VPWR circuit open
  • CV solenoid circuit shorted to PWR GND or CHASSIS GND
  • Damaged CV solenoid
  • CV solenoid circuit open
  • CV solenoid circuit shorted to VPWR
  • Damaged PCM

P1309 - Misfire Monitor Disabled When the misfire monitor is disabled, usually due to the input signal generated by the camshaft position (CMP) sensor, by sensing the passage of teeth from the CMP wheel.
  • Camshaft position sensor
  • Powertrain control module
  • ECT, MAF, and CKP sensors

with the codes you have here I would look in the direction of the egr valve first because that will cause the bucking and stalling, and the misfires, but so will the canister vent solonoid. the misfire codes and the cylinder overtemp code could be from overheating or because if the misfires.

Jul 27, 2009 | 1999 Ford Expedition

1 Answer

1995 mercury villager check engine code p1200 injector open


P0400 = EGR Flow
P0325 = knock sensor (Do not ever change a knock sensor, they don't affect anything and cost $600 to replace for absolutely no gain)
P1200 = I can't find this one. I think it's injector flow
report back on what you find.
Egr flow may be plugged egr passages or a bad solenoid.
--------------
1996 PCED OBDII-Villager SECTION 1B: Description and Operation
Exhaust Gas Recirculation System
Exhaust Gas Recirculation (EGR) System Operation The exhaust gas recirculation (EGR) system (Figure 1 below) recirculates a portion of the exhaust gases into the intake manifold under average vehicle driving conditions to reduce combustion temperatures and exhaust gas NOx content. The amount of exhaust gas recirculated varies according to operating conditions and will be cut completely under:
  • Engine starting condition
  • Low engine coolant temperature condition
  • Excessively high engine coolant temperature condition
  • Engine idling condition
  • High engine speed condition
  • Mass air flow sensor failure
The exhaust gas recirculation (EGR) system on the Villager uses the exhaust gas recirculation/evaporative emission (EGR/EVAP) control solenoid valve to provide vacuum to both the EGR valve and the EVAP canister when commanded by the PCM. If the exhaust backpressure is sufficient to close the EGR backpressure transducer valve, vacuum is sent to the EGR valve and allows EGR gas to flow into the intake manifold. If the exhaust backpressure is not sufficient, the EGR backpressure transducer will remain open and allow vacuum from the EGR/EVAP control solenoid to vent to the atmosphere.
The EGR system monitor, for OBD II regulations, uses an EGR temperature sensor to monitor the EGR system. The EGR temperature sensor is a thermister located in the EGR passageway. When hot exhaust gas is recirculated into the engine, the temperature at the EGR passageway increases. This increase is sensed by the EGR temperature sensor and a signal is sent to the PCM to indicate EGR flow. If the EGR temperature sensor does not detect EGR flow when commanded by the PCM after two consecutive drive cycles, the malfunction indicator lamp (MIL) will be illuminated and a diagnostic trouble code (DTC) will be stored. The MIL will be turned off after three consecutive drive cycles are completed with no malfunctions detected. The DTC will remain stored in the PCM memory until 80 drive cycles have been completed without the same malfunction detected in the system.
Figure 1: Exhaust Gas Recirculation (EGR) System Diagram Item Number Description 1 — EGR/EVAP Control Solenoid 2 — Air Cleaner Housing 3 — Throttle Valve 4 — EGR Temperature Sensor 5 — EGR Valve 6 — EGR Backpressure Transducer 7 — EVAP Canister
Exhaust Gas Recirculation (EGR) Backpressure Transducer Valve The exhaust gas recirculation (EGR) backpressure transducer valve is used to control EGR. The EGR valve is operated by ported vacuum, but the ported vacuum will normally be vented off at the EGR backpressure transducer valve. As rpm increases, exhaust pressure increases and pushes on the diaphragm in the EGR backpressure transducer valve and closes the vacuum vent.
Figure 2: EGR Backpressure Transducer Value
Item Number Description 1 — Throttle Valve 2 — Vacuum Port 3 9D475 EGR Valve 4 9F452 EGR Backpressure Transducer Valve 5 — EVAP Canister 6 — EGR/EVAP Control Solenoid 7 — Vent
EGR/EVAP Control Solenoid The exhaust gas recirculation/evaporative emission (EGR/EVAP) control solenoid (Figure 3) is controlled by the powertrain control module (PCM). The EGR/EVAP control solenoid controls vacuum to both the exhaust gas recirculation (EGR) valve and to the evaporative (EVAP) emission canister. When the EGR/EVAP control solenoid is off (12 V signal from the PCM) vacuum is supplied to both the EGR valve and to the EVAP canister. When the EGR/EVAP control solenoid is on (ground supplied by PCM) vacuum is vented to the atmosphere keeping the EGR valve closed and no vacuum to the EVAP canister. The PCM will command the EGR/EVAP control solenoid on at:
  • Engine starting condition
  • Low engine coolant temperature condition
  • Excessively high engine coolant temperature condition
  • Engine idling condition
  • High engine speed condition
  • Mass air flow sensor failure
Figure 3: Exhaust Gas Recirculation/Evaporative Emission (EGR/EVAP) Control Solenoid
Exhaust Gas Recirculation (EGR) Temperature Sensor
The exhaust gas recirculation (EGR) temperature sensor (Figure 4) is a thermister type sensor that monitors the temperature of the exhaust in the EGR passageway. As the EGR flow increases, the temperature increases. This process creates a change in the resistance of the sensor, which decreases as the temperature increases. The signal is sent to the powertrain control module (PCM) to indicate that the EGR system is working properly. If the EGR temperature sensor does not change resistance as the PCM expects on two consecutive drives, the malfunction indicator lamp (MIL) will be illuminated and a diagnostic trouble code (DTC) will be stored.
Figure 4: EGR Temperature Sensor Exhaust Gas Recirculation (EGR) Valve
The exhaust gas recirculation (EGR) valve (Figure 5) recirculates portions of the exhaust gas back into the intake manifold to reduce the amount of the NOx released during combustion and to reduce combustion temperature. The amount of exhaust gases that are released into the engine is proportional to the load on the engine.
Figure 5: EGR Valve

Mar 20, 2009 | 1995 Mercury Villager

1 Answer

I am having trouble getting my check light to go off after I had it checked and the EGR valve was replaced. The light comes back on after about 15 miles of driving and the code reads EGR poor flow. I can...


Insufficient EGR Flow Detected

Possible Causes:
DPFE sensor signal circuit is shorted to ground
DPFE sensor VREF circuit is open between sensor and PCM
DPFE sensor downstream hose off or plugged
DPFE sensor hoses both off, loose or damaged
DPFE sensor hoses connected wrong (reversed)
EGR orifice tube is damaged or restricted
PCM has failed
And what sets the code is…….Engine started, engine running in closed loop under steady cruise conditions, and the PCM detected the DPFE sensor input indicated insufficient EGR gas flow. Run the KOER Self-Test, and if DTC P1408 is present, the fault is currently present. This code sets in 2 Trip(s). The light will stay on until the cause is repaired. A bad EGR valve is only on possible cause.

Hope this helps,

Dave

Feb 28, 2009 | 2002 Ford Mustang

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