I have a 94 Ranger Supercab 4.0L with a manual trans. About a month ago I got the old "Check Engine" light while driving. It would come on occasionally for a few seconds and then off but the truck seemed to run fine. I whipped out my trusty code reader and in the " Continuous Memory" it shows a code "332" which translates to "Insufficient EGR flow detected". So, is it the EGR valve or the unit that controls the EGR valve that is causing the problem. Is there any way to figure out which one it is?
Thanks

 

Was your truck originally sold in Cal? Those were the only 4.0's that had EGR for that model year. If you're not sure, look under the hood at the stickers and see if it says something about Cal emissions or look to see if the EGR system is present.

 

Check out this thread it should help https://www.ford-trucks.com/forums/s...ht=%25252Bdpfe

 

To determine the exact cause of a code you need to run the pinpoint test for the code.

 

Agreed, you should make sure you have an EGR system first, as I recall reading about a wild goose chase or two and then it turned out that the motor(s) didn't originally have the EGR system to begin with, yet people were getting EGR codes anyway!

Like Cowboy mentioned, those '94 models can be tricky because of CA emissions requiring the EGR system to be used in CA vehicles that year. Then comes 1995, and that is also a tricky year because of it being transitional as far as OBD-II replacing EEC-IV.

Anyway, if they exist, then you should be able to locate both the EGR valve and also the EGR sensor on your 4.0L, they can be found just below the part of the upper intake where the idle air control (IAC) valve is mounted.

 

DTC 332 indicates the PFE/DPFE sensor signal to the Powertrain Control Module (PCM) did not change when the PCM output a duty cycle to the EVR solenoid requesting EGR flow.

Possible causes are:

-- Vacuum hose leaks.

-- Obstructed vacuum hoses.

-- Damaged EVR solenoid.

-- Damaged PFE/DPFE sensor.

-- Damaged EGR valve.

-- Damaged PCM.


[START PINPOINT TEST]

l Key off.

l Disconnect and inspect vacuum hose between EVR solenoid and EGR valve for blockage, kinks, etc. Service as necessary and reconnect after inspection.

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

l Rerun Key On Engine Running (KOER) Self-Test while observing vacuum gauge.

l Is vacuum reading less than 1 in-Hg (3kPa) throughout the test (disregard DTC output)?

Yes
REMOVE vacuum gauge. GO to «DL31».

No
REMOVE vacuum gauge. RECONNECT EGR valve vacuum hose. RERUN Quick Test if the vacuum hose was not in good condition and service was completed. Otherwise, GO to «DL34».


DL31 CHECK VACUUM INPUT TO THE EVR SOLENOID

l Key off.

l Disconnect source vacuum hose at EVR Solenoid and connect hose to a vacuum gauge.

l Start the engine and let it idle while observing the vacuum gauge.

l Is vacuum above 15 inches at idle?

Yes
INSPECT vacuum hose from EVR Solenoid to EGR valve. If OK, REPLACE EVR solenoid. RERUN «Quick Test».

No
REPLACE the vacuum line connecting EVR solenoid to source vacuum. RERUN «Quick Test».


DL34 CHECK SIGNAL AT THE PFE/DPFE INLET HOSE(S)

l Key off.

l Disconnect and inspect the PFE/DPFE inlet hose(s) for kinks, blockages, etc. Service as necessary and reconnect after inspection.

l Tee in a standard vacuum gauge at the PFE/DPFE inlet hose (downstream signal).

l Rerun KOER Self-Test.

l Is there a momentary increase in vacuum gauge reading during KOER Self-Test (indicating EGR valve is opening?

Yes
REMOVE vacuum gauge. RERUN Quick Test if the inlet hose(s) needed service. If service was not needed, then GO to «DL35».

No
REMOVE and INSPECT the EGR valve for signs of contamination, unusual wear, carbon deposits, grinding, and other damage. SERVICE as necessary (use Rotunda 021-80056 EGR valve cleaner if needed). RERUN «Quick Test».


DL35 ATTEMPT TO GENERATE KOEO DTC 337

l Key off.

l Disconnect PFE/DPFE sensor.

l Jumper VREF circuit to PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector.

l Perform KOEO Self-Test.

NOTE:
If no DTCs are generated, immediately remove jumper and go directly to «DL37».

l Is DTC 337 present (ignore all other DTCs)?

Yes
REPLACE PFE/DPFE sensor. REMOVE jumper wire. RERUN «Quick Test».

No
REMOVE jumper. GO to «DL36».


DL36 MEASURE VREF CIRCUIT VOLTAGE

l Key off.

l PFE/DPFE disconnected.

l Key on, engine off.

l Measure voltage between VREF circuit and SIG RTN circuit at the PFE/DPFE sensor vehicle harness connector.

l Is voltage between 4.0 and 6.0 volts?

Yes
GO to «DL37».

No
GO to Pinpoint Test Step «C1».


DL37 CHECK PFE/DPFE HARNESS CIRCUIT CONTINUITY

l Key off.

l PFE/DPFE sensor disconnected.

l Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.

l Install breakout box, leave PCM disconnected.

l Measure resistance between PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector and Test Pin 27 at the breakout box.

l Is resistance less than 5.0 ohms?

Yes
GO to «DL38».

No
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RERUN «Quick Test».


DL37 CHECK PFE/DPFE HARNESS CIRCUIT CONTINUITY

l Key off.

l PFE/DPFE sensor disconnected.

l Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.

l Install breakout box, leave PCM disconnected.

l Measure resistance between PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector and Test Pin 27 at the breakout box.

l Is resistance less than 5.0 ohms?

Yes
GO to «DL38».

No
SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RERUN «Quick Test».


DL38 CHECK PFE/DPFE HARNESS CIRCUIT FOR SHORTS TO GROUND AND SIG RTN

l Key off.

l PFE/DPFE sensor disconnected.

l Breakout box installed, PCM disconnected.

l Measure resistance between PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector and Test Pins 40/60 at the breakout box.

l Measure resistance between PFE/DPFE circuit at the PFE/DPFE sensor vehicle harness connector and Test Pin 46 at the breakout box.

l Is each resistance greater than 10,000 ohms?

Yes
REPLACE PCM. REMOVE breakout box. RECONNECT all components. RERUN «Quick Test».

No
SERVICE short circuit. REMOVE breakout box. RECONNECT all components. RERUN «Quick Test».

 

Yes, it has an EGR Valve and it is a California truck as I am the original owner and bought it in CA! Thanks a lot!! for the "Pin Point Test"!! I'll let you know what I find!
Later,

 

I have a 95 xlt that gave me an inseffeciant egr flow code and it was fixed by removing the egr valve and cleaning out the hole in the intake.When you remove the egr valve there will be a finger sized hole where it was mounted,at the bottom of this is a SMALL hole,it needs to be poked out with a stiff peice of wire and then cleaned more with a pipe cleaner or something.Then remove the negative battery cable for five minutes to clear the code.

 

Check for plugging downstream of the EGR valve. This picture shows just how bad it can be. Both me (98 expedition) and my brother in law (98 F150) had same problem. Codes showed low EGR flow. Tried all the suggestions first, bought new DP switches, etc. All the time it was this simple ugly plugging. Relative easy to clean after removing throttle body.

A business card is inserted in TB so you can see black sludge ball. There are two one for each port and there shadows on the card. Passage ways totally plugged. Used coat hanger to clean.