KOEO test will not run
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
KOEO test will not run
The KOEO test will not run on my 1994 F150 5.0L E4OD truck.
The engine does start and run just fine.
When you try to the run the self-test, the fuel pump will come on for the one second run time and then shut off but nothing after that.
The Truck Battery is fully charged.
New batteries in the Innova 3145 Ford Code Reader.
But the PCM will run the KOEO test on the bench OK with the PCM Tester and the Innova 3145 Ford Code Reader.
Tried two different PCM's and the same thing. They run on the bench but not on this truck and will also run the test in another truck.
I have tried running the test with the Engine plug, Transmission connectors, Heated Oxygen Sensor, and the MAF sensor all disconnected. It still will not run KOEO self-test.
Put the Brake Out Box (BOB) on it to bypass the Self-test connector and still no go.
Voltages and grounds check out with the BOB.
Also opened up the PCM's and they both look new inside, I did replace the caps in one of them.
The engine does start and run just fine.
When you try to the run the self-test, the fuel pump will come on for the one second run time and then shut off but nothing after that.
The Truck Battery is fully charged.
New batteries in the Innova 3145 Ford Code Reader.
But the PCM will run the KOEO test on the bench OK with the PCM Tester and the Innova 3145 Ford Code Reader.
Tried two different PCM's and the same thing. They run on the bench but not on this truck and will also run the test in another truck.
I have tried running the test with the Engine plug, Transmission connectors, Heated Oxygen Sensor, and the MAF sensor all disconnected. It still will not run KOEO self-test.
Put the Brake Out Box (BOB) on it to bypass the Self-test connector and still no go.
Voltages and grounds check out with the BOB.
Also opened up the PCM's and they both look new inside, I did replace the caps in one of them.
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
CODE READER TROUBLESHOOTING GUIDE If all procedures are followed and the Code Reader will not retrieve codes when performing the Key On Engine Off (KOEO) Self Test, check the following: 1. Code Reader's batteries, change batteries as required. 2. Check the vehicles Test Connector pins for corrosion and clean as necessary. NOTE: The Code Reader receives a ground signal from one of the pins of the vehicle's Test Connectors and uses it to signal the computer to initiate the Self-Tests. A problem in the vehicle's Test Connector ground pin or circuit will result in an improper ground being supplied to the code reader which will effect the code reader's ability to signal the computer to initiate the Self Test. If after performing the procedures in step one and two, the code reader still does not work proceed to EEC-IV Systems/ MCU Systems bellow (as applicable).
https://static.summitracing.com/glob...s/equ-3145.pdf
https://static.summitracing.com/glob...s/equ-3145.pdf
Thread Starter
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
I have used three PCM and they all do the same thing on the truck.
All three will do a self-test and flash out codes when on the bench hooked to the PCM tester.
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Thread Starter
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
CODE READER TROUBLESHOOTING GUIDE If all procedures are followed and the Code Reader will not retrieve codes when performing the Key On Engine Off (KOEO) Self Test, check the following: 1. Code Reader's batteries, change batteries as required. 2. Check the vehicles Test Connector pins for corrosion and clean as necessary. NOTE: The Code Reader receives a ground signal from one of the pins of the vehicle's Test Connectors and uses it to signal the computer to initiate the Self-Tests. A problem in the vehicle's Test Connector ground pin or circuit will result in an improper ground being supplied to the code reader which will effect the code reader's ability to signal the computer to initiate the Self Test. If after performing the procedures in step one and two, the code reader still does not work proceed to EEC-IV Systems/ MCU Systems bellow (as applicable).
I have also changed batteries in the code reader and the code reader work OK on the bench with the PCM tester.
When push test on the reader while hooked to the truck the fuel pump will run for one second and quit so the reader is seeing a ground through the PCM.
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Thread Starter
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
This has gone on from the first day I got the truck and I think others have looked at this problem before I bough the truck.
Thanks to everyone that has replied.
Logistics Pro
Joined: Nov 2013
Posts: 3,929
Likes: 1,199
From: Mojave, Ca
Odd that the engine runs good but the ECU won't spit out codes.
As far as I know, the logic for EEC-IV is powered by the 5v converter that's built into the ECU. The 5v converter also runs a bunch of the engine sensors like the TPS and EGR position sensors.
Id start by pulling out the wiring diagram and disconnecting EVERY 5v component on the harness, and see if it'll spit out codes. If it does, then start plugging components back in until it won't spit out codes. Once you've identified the component, start digging into why it failed.
As far as I know, the logic for EEC-IV is powered by the 5v converter that's built into the ECU. The 5v converter also runs a bunch of the engine sensors like the TPS and EGR position sensors.
Id start by pulling out the wiring diagram and disconnecting EVERY 5v component on the harness, and see if it'll spit out codes. If it does, then start plugging components back in until it won't spit out codes. Once you've identified the component, start digging into why it failed.
Thread Starter
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
Odd that the engine runs good but the ECU won't spit out codes.
As far as I know, the logic for EEC-IV is powered by the 5v converter that's built into the ECU. The 5v converter also runs a bunch of the engine sensors like the TPS and EGR position sensors.
Id start by pulling out the wiring diagram and disconnecting EVERY 5v component on the harness, and see if it'll spit out codes. If it does, then start plugging components back in until it won't spit out codes. Once you've identified the component, start digging into why it failed.
As far as I know, the logic for EEC-IV is powered by the 5v converter that's built into the ECU. The 5v converter also runs a bunch of the engine sensors like the TPS and EGR position sensors.
Id start by pulling out the wiring diagram and disconnecting EVERY 5v component on the harness, and see if it'll spit out codes. If it does, then start plugging components back in until it won't spit out codes. Once you've identified the component, start digging into why it failed.
The 5 volt output is 5 volts on the test PCM tester on the bench.
Also it has the 5 volt output in the truck.
Thread Starter
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Fleet Owner
Joined: Aug 2005
Posts: 23,668
Likes: 301
From: Easton,Ks
Maybe but what circuit broken would cause this.
It did run code once last week and the only KOEO code it output was for the SS2 circuit. It also gave a 111 for the stored codes.
Fixed that open wire in the transmission harness. Then it went back to no self-test.
Only the fuel pump running for one second each time STI was grounded.
It did run code once last week and the only KOEO code it output was for the SS2 circuit. It also gave a 111 for the stored codes.
Fixed that open wire in the transmission harness. Then it went back to no self-test.
Only the fuel pump running for one second each time STI was grounded.
Logistics Pro
Joined: Nov 2013
Posts: 3,929
Likes: 1,199
From: Mojave, Ca
Hotshot
Joined: Jul 2020
Posts: 10,569
Likes: 2,678
From: Near Salt Lake City
Have you gone through the pinpoint tests for no codes outputted?
You will see / find your problem if you run through those
For a 1994 they are in the PCED
You should own one of those
You will see / find your problem if you run through those
For a 1994 they are in the PCED
You should own one of those