crazzywolfie

i was wondering if there is a reason the check engine light would stay on. my dads 95 f150 with 4.9 and 5 speed standard transmission has done this twice on me. only way i was able to get it to shut off was to turn the truck off and turn it back on. i have tried checking for codes but all i got was 538 and 332 which i think got because i messed up the test. i had thought the issue might have originally been related to the bad map sensor but since i replaced the map sensor the other day and things seem to run better i figure that should not be the issue. also the oil pressure gauge stopped working not sure if that would be related or not. it quit working a couple weeks ago but truck runs fine and don't make any bad noises. it also got broken sensor on the drivers side. i think my dad broke it years ago when he replaced the drivers side motor mount but we have never been able to identify what it is to replace it.

mtnative

1. 538 is a operator failure during a test sequence.

2. DTC 332 in Key On Engine Running (KOER) indicates the EVP sensor input did not change after the EVR solenoid was instructed by the Powertrain Control Module (PCM) to open the EGR valve.

Continuous Memory DTC 332 indicates the EGR valve did not open with the engine stabilized and the EVR solenoid duty cycle present sometime during vehicle operation.

In other words 332 means that the PCM ask the EGR valve to open and the EVP sensor toll the PCM that it did not.
This could be other things like:
1. the vacuum hose has a hole in it, the green one
2. the EGR solenoid is bad
3. no vacuum to the solenoid
4. bad or not preloaded EVP sensor
5 bad wiring from the EVP to the PCM
6 bad wiring from the PCM to EGR solenoid
7 bad plugs or pins on any of the four plugs.

crazzywolfie

but that shouldn't keep the check engine light on should it? at one point in time the check engine light would come on for a minute and then go off and i would never see it again for a while.

dubcnea

mine used to do that. on for a minute, then off for a long time. eventually it was on more than it was off. i replaced the EVR and EGR only to find out that a couple of my vac lines were destroyed, causing a major vac leak.

i've since replaced all the tubes with rubber hose (5/32") and that has fixed the issue (until recently..back to 332/334 codes...so i need to check that). but the light will stay on as long as there is an issue that the computer can't fix itself (or a part does not eventually obey).

Warlockk

Like mtnative says you have an EGR error. Of course it will turn in the CEL. The CEL was designed specifically for emissions errors. At the moment the error is intermittent. Its likely the valve is starting to stick. Or like dubncea says its possible the solenoid has a small leak or there is a loose or corroded wire. Eventually it will stop working and you will have a permanent light. It requires 2 cycles of error to illuminate the light then if it doesn't happen again the light turns off and just leaves a code. Fix it before it becomes an issue. Symptoms will include possible loss of power, engine ping, missfire bad idle and poor mpg depending on the actual cause.

crazzywolfie

but the check engine light is not coming on every time i drive the truck. i can drive around all day and not have it come on at all. it when it comes on and stays on it can be pretty random. i know 1 morning the light came on after the engine had be running for only 20-30 minutes. engine seems to run pretty good since i replaced the map sensor.

Just call me Sean

iTrader: (1)

So what? The light doesn't even have to come on for there to be codes.

dubcnea

if you have a part that's failing then it may not be failing enough to trigger the CEL. check for codes and see if it's leaving them even when the light does not come on. ensure you clear the codes before you are done so you can ensure that any codes you find later without a light are new and not just the same codes you've already checked.

Warlockk

As dub just pointed out and I stated earlier the ecu runs a system test every so often. Its very slow on our old computers. For this code it must catch the error on 2 consecutive test cycles. It then sets a code and turns on the light. If it runs another check and it works fine then the light turns off and the code remains for a certain number if drive cycles. A drive cycle is the car running and meeting certain sets of parameters to run all the tests. It includes reaching a certain temperature, hitting different RPM s starting and stopping and driving varying speeds and distances. It can sometimes take several days to meet a drive cycle. So with an intermittent failure the light will come and go. Some faults are deadlines that will actually shut the engine down or set it to limp mode on the first detection. Newer computers are much faster and the tests happen more often so you have fewer intermittent issues.