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Discussion Starter · #1 ·
Need help, got a really high idle. Pulled codes with KOEO test got these:
654 Transmission selector not in park.
452 Vehicle Speed Sensor Problem
173 Oxygen sensor not switching – system is or was rich
334 EVP sensor is/was high.

This is a 1992 bronco. Thing is idling at about 2500.

When I try to KOER, I never get the blinks telling me to turn wheel/hit brake/od switch, the CEL just stays solid. Anyone, ideas?

All the vacuum lines I can find/see seem to be fine.
 

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654 could be an issue with your Transmission Range Sensor also called a MLPS (Manual Lever Position Sensor) If its original, I would change it with a New Motorcraft Part.

If you cant find a Motorcraft part, just get one from rockauto thats compatible. They are listed under "Electrical Switch and Relay" and are listed as "Neutral Safety Switch/Range Sensor"

They look like this.



Heres my write up to swap one out.
http://www.fullsizebronco.com/forum...191742-1994-bronco-e4od-mlps-replacement.html

If your O2 Sensor is bad, it wont be able to control the fuel mixture properly and could cause a high idle condition. Since you have a 173 code, I would look for an O2 sensor straight away and fix that first. This will likely get rid of your EVP code, but if it doesnt theres a thread for that as well.

http://www.fullsizebronco.com/forum...-position-evp-sensor-testing-replacement.html

Once you fix the O2 Sensor, clear your codes by disconnecting the positive and negative battery lead and ground the positive lead to the fender ground lug.

Then drive it for about 10 - 15 mins and see how it performs. Then go back home and pull codes again and see what you get. Sometimes fixing one major problem fixes all the other codes.

When fixing these codes, always start with the lowest number first.
 

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Discussion Starter · #4 ·
Just updating, I have not had a chance to work on this yet. But I will respond with how I end up fixing it so people googling the problem etc can hopefully find an answer. Thanks again, this community is awesome.
 

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Yo 92,
J Owens gave the right-on info.. here is my long-winded addition:DTC 522 & 654 indicate the gear selector was not in Park during Self-Test; "...Possible causes: Misadjusted linkage. Open or short in harness circuits. Damaged TR sensor. Damaged Powertrain Control Module (PCM). OR CHECK THIS OUT, TECHNICAL BULLETIN # 230A, TRANSMISSION: E4OD SUBJECT: No upshift 4th gear starts, harsh upshifts, neutrals out after shifts APPLICATION: Ford-E/F Series, Bronco DATE: Jan 1995 NOTE: Click on image to make it larger. All of these concerns can be the result of an inappropriate Manual Lever Position (MLP) sensor signal. The MLP sensor consists of six resistors connected in series (ganged). The resistance of the MLP sensor will vary based on which range the transmission is in. The MLP circuit can be checked using the following steps. (Step 1) Check the MLPS ground: Turn the ignition on. The voltage on pin 46 (sensor ground ) should not exceed .1v. If the voltage is excessive, add an additional ground to the existing ground wire (figure 2). NOTE: Click on image to make it larger. Figure 2 Splice an additional ground from the existing ground wire to a known good ground.The negative post of the battery is the best. This view is of the pins of the MLP connector pins. NOTE: Click on image to make it larger. (Step 2) Check the MLPS voltage: The voltage at pin 30 should vary-in increments- according to the position of the manual lever (figure 3). MLP voltage (ignition on) should be within 20% of these specifications. Note It is recommended that you use a break-out box. If a break-out box is not available, you will need to pierce the wires to pins 30 and 46 for these tests. NOTE: Click on image to make it larger. (Step 3) Check the resistance of the MLPS: The resistance of the MLPS (pins 30 and 46) should change-in increments-with the position of the manual lever (figure 4). Note If this test is being done with a break-out box, disconnect the computer first (make sure the ignition is off). If this test is being done without a break-out box, disconnect the MLPS from the vehicle harness. Note Testing beyond this point will include tests of the harness. Consult the appropriate repair manual for this..."
Source: by fordbronco1995 ("JUICE") at FSB DTC 522 & 654 indicate the gear selector was not in Park during Self-Test; "...Possible causes: Misadjusted linkage. Open or short in harness circuits. Damaged TR sensor. Damaged Powertrain Control Module (PCM). OR CHECK THIS OUT, TECHNICAL BULLETIN # 230A, TRANSMISSION: E4OD SUBJECT: No upshift 4th gear starts, harsh upshifts, neutrals out after shifts APPLICATION: Ford-E/F Series, Bronco DATE: Jan 1995 NOTE: Click on image to make it larger. All of these concerns can be the result of an inappropriate Manual Lever Position (MLP) sensor signal. The MLP sensor consists of six resistors connected in series (ganged). The resistance of the MLP sensor will vary based on which range the transmission is in. The MLP circuit can be checked using the following steps. (Step 1) Check the MLPS ground: Turn the ignition on. The voltage on pin 46 (sensor ground ) should not exceed .1v. If the voltage is excessive, add an additional ground to the existing ground wire (figure 2). NOTE: Click on image to make it larger. Figure 2 Splice an additional ground from the existing ground wire to a known good ground.The negative post of the battery is the best. This view is of the pins of the MLP connector pins. NOTE: Click on image to make it larger. (Step 2) Check the MLPS voltage: The voltage at pin 30 should vary-in increments- according to the position of the manual lever (figure 3). MLP voltage (ignition on) should be within 20% of these specifications. Note It is recommended that you use a break-out box. If a break-out box is not available, you will need to pierce the wires to pins 30 and 46 for these tests. NOTE: Click on image to make it larger. (Step 3) Check the resistance of the MLPS: The resistance of the MLPS (pins 30 and 46) should change-in increments-with the position of the manual lever (figure 4). Note If this test is being done with a break-out box, disconnect the computer first (make sure the ignition is off). If this test is being done without a break-out box, disconnect the MLPS from the vehicle harness. Note Testing beyond this point will include tests of the harness. Consult the appropriate repair manual for this..."
Source: by fordbronco1995 ("JUICE") at FSB

READ MORE and see diagrams


Manual Lever Position/Transmission Range (MLPS/TR) Sensor

Connector Pin-Out Diagram
Source: by Ryan M (FireGuy50) at http://oldfuelinjection.com/files/Trans_harness.gif

Connector Re-Pining; "...according to the connector instruction sheet that came with the new connector. wires positions by circuit # are exactly the same from old to new. there is no mention of wire color. the wires are designated by circuit # so basically one at a time take each wire out.... and put it in the same place it came out of on the new connector..."
Source: by thePUNISHER (Paul) at FSB

Connector Re-Pining; "...was a spring type clip that's a part of the pins. I think I used a jeweler's screwdriver alongside the pins to release them. I don't remember which side worked best, but one end was better. It seemed real tough until I found the right place for the screwdriver, then they popped out easily. Move them over one at a time to keep the order..."
Source: by ElKabong (Ken, El Kabong) at FSB
Wiring Diagram in a 94 from EVTM; from C103 to Starter
Source: by Mikey350 at SuperMotors.net 1996 Ford Bronco '94 EVTM picture | SuperMotors.net


Testing
Source: by SeattleFSB (Seattle FSB) at SuperMotors.net 1990 Ford Bronco E4OD Transmission picture | SuperMotors.net
 

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Discussion Starter · #6 ·
Thank you, Ive just now got the time to start work on it, came back to say I replaced the o2 sensor and it made a big difference. Truck stalls now when put into Drive or reverse. It is low on fluid, today I am going to take pan off put in new gasket and filter and oil. What does the MLPS do? I dont have a new one of those yet, It's giving me the code telling me its wrong, but the truck shifts beautifully?
 

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it tells the computer what gear you are in. basically its one of the most important sensors on the vehicle. If it doesnt work right, you will feel like your driving down the road and it suddenly goes into neutral. There are other things it does as well depending on what the problem with it is. If its an intermittent signal, expect all kids of really strange behavior, like slamming into gears, problems downshifting. its a very easy fix. its just $80. I know not everyone has $80 burning a hole in their wallet, but its important and worth replacing. You can always hit the junk yard and look for one that looks to be newer, or cleaner than the one you have. that would make it $5.
 

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Discussion Starter · #8 ·
Thank you, I am going to get a new one, I have the $ just not the time, between 2 kids and work, I get about 30mins-hour a day. From what I found as symptoms on the web the MLPS isn't bad as I have none of those problems. However, the codes pulled do flag it. I certainly will replace it, but for anyone googling that stumples here replacing the o2 sensor was as huge deal and if you have similar scenarios you should do the same.
 

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Discussion Starter · #10 ·
Thank you mikey350 will give this a shot tomorrow, sorry I don't reply daily. I just don't have much free time to knock this whole thing out in a week. Like always in guess someone ends up here from google or any other reason will reply with things that fixed problems.
 

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Check for vacuum leaks. With an idle that high I'd expect a substantial one
 

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I have seen EGR valves fail and cause a high idle when the diaphragm tears?? But then you get an EGR position sensor code I guess?
Yo 445,

Here ya go:
EGR Valve Position (EVP) Sensor Testing & Replacement by Seattle Bronco
I was noticing my engine seemed to have less power than usual and it would die once when the idle dropped on cold start-up. I initially guessed that maybe my ECT Sensor was possibly out of range showing warm causing the engine to idle down when not fully warmed up. So I decided to check for Diagnostic Trouble Codes to see what was up.

Using my Equus 3145 Ford OBD-I Code Reader, I received the following DTC Memory Codes:

DTC 327 – EGR valve position circuit below minimum voltage
DTC 334 – EGR closed valve voltage high

Read much more
 
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