I’m trying to clear my check engine light, but I can’t seem to get my codes to go away. The codes I’m getting are, 51, 22, 53, 54, and 35. I have replaced the EGR Valve, EGR Sensor, the MAP Sensor, the Intake air sensor, the throttle positioning sensor, and the coolant temp sensor. I’m not the greatest mechanic in the world, but I have replaced everything I’m getting a code for and every code remains

 

Welcome to the forum

What YEAR Ranger?
And what engine?

Assuming 1992 or older as those used 2 digit trouble codes

You should list the definitions with the codes, for two reasons, first is that NO ONE has them memorized, lol, and second YOU may have got the wrong definition
22 MAP (vacuum) or BARO signal out of range - MAP

35 EVP - (R) Engine RPM's too low to test EGR system - EVP
EVR - (O, R, M) EVP sensor signal is/was high - EVR
PFE - (O, R, M) PFE sensor signal is/was high - PFE

51 Engine Coolant Temperature (ECT) sensor signal is/was too high - ECT
53 Throttle Position sensor too high - TPS
54 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal high - IAT VAT

Here is what stands out on this list of codes, they ALL share the same 5volt power supply inside computer
There is a Grey/red stripe wire at each of these sensor, its just daisy chained from one sensor to the next, and comes from the computer

After 20years or so the 2 or 3 capacitors in the engine computer can leak and fail which will cause running issues and odd codes
Not hard to fix, and costs under $5
Pull out the computer and check the 60-wire connector for corrosion
Open up computer and have a look at the circuit board, easy to see corrosion or other issues
There will be 2 or 3 black or blue cylinder type capacitors sticking up, it can be obvious that they are leaking or not, but replace them in any case because they WILL fail

So open that computer up and have a look

And just a heads up, sensors rarely fail, they are often replaced, but rarely need to be
Usually if you just unplug the sensor's connector and plug it back in that will clean off the terminals enough to get sensor working again
This is why people "think" a sensor was bad when they replace it, because "new" sensor fixed the problem, it did fix it but not because is "new", lol, unplugging the old old and plugging in the new one fixed it

Only sensor that NEEDS to be replaced is the O2 sensor, it uses a chemical to detect Oxygen in exhaust, and chemical just gets used up, so these need to be changed every 150k miles or 12 years which ever comes first, not negotiable, change it or them

If you have a volt meter, set it to DC Volts and with key ON test one of the grey/red wires for 5volt

 

I just seen your response! I will definitely check the computer to look for corrosion!

The truck is a 1989 2.3l!

I did find a temporary fix to all of the codes. I basically spliced into the ground wire going to my MAP sensor, and grounded it straight to the battery. This cleared all of my codes. So apparently that wire is not grounded properly somewhere.

Unfortunately it runs behind the intake manifold, and it is very difficult to follow.

I have left the ground hooked to the battery, and it does continue to work, but now I am getting new codes. I am getting code 33 saying that my EGR valve isn’t closing, and code 41 saying my 02 sensor is reading lean. I have replaced the 02 sensor, my EGR valve, and my EGR sensor, but unfortunately this did not fix my problem.

The only time it affects the truck is when the engine is fully warm. When it’s up to temperature I have to push the throttle all the way to the floor or it Boggs down.

Thanks for the help! I’m new to the forum so I’m still learning, and I’m also a pretty novice mechanic!

 

You may have cause more problems by grounding that wire

Sensors are all grounded to the computer, so the voltage difference, the signal, has common reference point
We all think ground as just 0volts, and it is but...........it can be 0.01v and when dealing with sensor voltages which are all under 5volts that can make a difference
So the sensor voltage, the signal is the difference between computers ground and 5volts(provided by the computer)
If you use battery negative, which SHOULD BE same as computers ground, then you can cause false differences in sensors signals

If a 12v wire is corroded then 12volt bulb won't be as bright, because voltage is reduced by higher resistance where it's corroded
Same thing happens when the Ground wire of the same bulb is corroded, it not 0volts its -5volts so only 7volts is passing thru the bulb and its dimmer

MAP sensor should have 3 wires, 5volt, Signal, Reference
5v wire is usually closest to Vacuum hose
Reference(ground) is farthest away
Center wire is signal

What color is the wire on your MAP sensor that you grounded?
Brown/white wire is 5v
Grey/red wire is Ground reference, this wire runs to most sensors on the engine, its shared
Light green/black wire is signal

So if you think that the grey/red wire is broken then you can splice that to the grey/red wire on another sensor, and it changes to a black/white wire on most
Throttle sensor has the black/white wire ground reference you could use

 

I will take some pictures and let you take a look to verify. It seemed to me that the intake air sensor, EGR sensor, coolant temp sensor, and MAP sensor all shared a wire that was black with a white stripe. You have made me second guess it now. Thank you for explaining how I could have actually made things worse by splicing the wire to the battery. I’ll upload some pictures of how it currently is, and we can go from there. Thank you very much!

 

Yes, grey/red and black/white wires were splice together in the harness, you can test that with ohm meter

Seen in this wiring diagram: https://www.therangerstation.com/tec...ls2_9_2of3.JPG

At the bottom, C132, also spliced with orange O2 sensor wire, S128

This is so all sensors are "on the same page" with computer, as far as ground reference

 

This is an overall photo of my computer.

It seems like this black “compositor” may have leaked? I’m not sure as this is my first time ever looking at one. I would love some guidance!!!

This is a photo of the MAP sensor that I tapped into to add a ground. I tapped into the wire on the very left.

 

Yes, the black/white wire would be the computer ground, grey/red wire in some years


Yes, that capacitor looks like it was already replaced, and old one did leak but was clean up a bit, may want to replace it again and clean up again

Also replace the other two BLUE ones, one is in lower left corner in first pic

The blue ones are factory, the black ones are replacements now-a-days

 

So, I actually decided to go ahead and replace the computer. It was relatively inexpensive and was the easiest option. After I replaced the computer all of my CEL lights went away. The truck is running as it should, EXCEPT, when it gets up to temperature. I drive highway everyday to work, and when I get about halfway into my commute the truck starts bogging down unless at full throttle. After I stop I always get the same codes. Code 41 saying that the 02 sensor is showing “lean”, and code 33 saying that the EGR valve isn’t opening.

I have already installed a new 02 sensor, EGR valve, EGR sensor, and solenoid.

Not sure where to go from here, any ideas?

ps- it was also doing this before I changed the computer.

 

Do you have a Vacuum gauge?
O2 Lean can be from partially clogged exhaust, or misfires
Vacuum gauge can test for clogged exhaust


Do you have vacuum hose that fits the EGR Valve port?
You can hook that up to EGR Valve and then start engine
Suck on the hose and EGR Valve will start to open, this will cause engine to run rough, and stall if enough exhaust is added to intake
Repeat a few times to confirm EGR Valve is working, opening

If EGR valve is working then follow its vacuum hose back to the EGR Modulator/solenoid
It will have 2 vacuum hoses on it, from EGR Valve, and to Intake Manifold vacuum
Pull unit out
Test that it "clicks" open and closed when you apply 9-12volts, 9 volt battery works or use the car battery, there is no polarity, as long as one pin is + and the other - it will "click" open
Also put vacuum hose on either port and blow thru hose while activating it, should flow air when activated, block air when not activated

Those are the active components, besides the sensor itself on the EGR valve

If these work then its a wiring issue
The EGR solenoid should have 12volts on one wire with key on, the computer then grounds the other wire to send vacuum to EGR valve to open it

These are the 3 wiring diagrams
https://www.therangerstation.com/tec...ls2_3_1of3.JPG
https://www.therangerstation.com/tec...ls2_3_2of3.JPG
https://www.therangerstation.com/tec...ls2_3_3of3.JPG

Page 2 has the EGR solenoid wiring
Page 3 the EGR sensor, it shares 2 wires with TPS, brown/white and grey/red

If it is an EGR sensor wire issue, that CAN CAUSE the Lean code, because computer would try opening EGR repeatedly to get a reading from EGR sensor, this causes false Lean exhaust

 

So, I have applied vacuum to the EGR valve by just sucking on a piece of vacuum hose attached to it. It does open/close when I do that.

I have checked the EGR solenoid by grounding it while it engine is running. When I ground it out, the engine boggs severely at idle. (That means the solenoid is working properly correct?) I can also run a separate negative and positive from my battery and see if I can get it to operate if necessary.

Is my next step to go through the wiring to the EGR sensor?

Sorry for all the questions. I appreciate the help!

 

Yes, good testing, Grounding solenoid and having engine bog down was a good test, and it does mean solenoid valve is working, and EGR Valve

So either EGR sensor is not reporting EGR valve position OR computer is not grounding EGR solenoid, either would cause the code 33

 

So I replaced the computer recently, as well as the EGR sensor. Seems like my wiring is to blame.

I am not good with wiring. At all.

Wish me luck!

 

Just pull the connector off the computer and test if each wire has "continuity" to its other end

Most meters have a DIODE test, select that and touch the two probes together, should hear a tone that means there is a connection
Or you can use OHMs, touch probes together and you can see 0 ohms meaning there is a connection

Then get a longer test wire, and test it first, lol, to make sure its OK
Then put this jumper wire at one end of wire to test and test other end

 

Well.. I got a longer wire to test continuity.. the wire tested good LOL, but so did all three of the wires to my sensor....

I touched one end of my multimeter to each wire in the plug, then checked at the computer side of the wire.. each wire had continuity...

I’m definitely baffled now.. any ideas?

 

What about the "ground wire" for the solenoid?
Brown/pink wire at pin 33 on computer, page 2 in above diagrams

 

I’ll check that one now!!!

 

Well I checked the wiring on the solenoid that goes to pin 33. It’s a green wire.. and guess what.. it has continuity.. only wire left is a red wire to the solenoid.. have to try to find where it goes

 

Red wire works from your test of grounding the solenoid and engine stumbling
But red wire comes from PCM(EEC) Relay, IAC valve has same red wire, you can test if those 2 red wires have continuity to each other, if so Red wire at solenoid is OK

So either computer is NOT grounding solenoid(computer issue), or new EGR sensor is bad

 

Just realized that the red wire on the solenoid is just the power wire... it shows 12v with the key on

 

I have tried my original sensor, and the new sensor on the new EGR valve. Unfortunately neither made a difference.

The EGR valve I bough is a off brand that was kind of cheap. Could that be causing my problem?

There is severe carbon build up in my original EGR valve, so I’m going to pull the exhaust tube off and see if it’s clogged. Not sure if it will make a difference or not.

 

Lets try this
Put that longer vacuum hose on the EGR valve so you can suck on it, we already know that caused the engine to stumble, so valve is working

There are 3 wires connected to EGR sensor, see page 3 above
5volt - brown/white wire
reference ground - grey/red wire
Signal wire - brown/light green

Test voltage on the signal wire, key on engine off, while you suck on the hose to open and close EGR valve

If should be changing in the 1 to 4volt range, if not then sensor is not moving with EGR valve
Maybe its not touching

If I remember correctly this type of EGR sensor looks like this: https://www.partsgeek.com/assets/dim...67-1201077.jpg

The stick is pushed up and down by EGR valve opening and closing
If you have a 3rd party EGR valve then maybe it not touching

If voltage on signal wire is not changing then pull the sensor off and test by manually moving the stick

 

Okay.. so, I manually opened the EGR Valve by sucking on it, and checked for voltage on the brown/green wire. It definitely changed when I opened the egr valve. But it never even reached 1v. I pulled the sensor, and manually pushed the button.. same thing, less than 1v. I checked the power wire to the sensor, it shows 5v. So is it not sending enough power over?

 

I checked it again to be sure. I grounded my tester better and it sent 5v. I noticed that the voltage increases as the pin is pushed in, is it possible that my EGR valve isn’t pushing it in far enough? Or would that not matter?

 

Forgot about this GREAT reference site, even have it bookmarked: Fuel Injection Technical Library

Look here at the expected voltages, on the two types of EGR Position sensors: Fuel Injection Technical Library » EGR Valve Position sensor (EVP)

So yours is way out of range, under 1v, even moving the pin manually