CONFUSING code combonation...
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Postmaster
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From: Pleasant Hill, MO
CONFUSING code combonation...
Alright, new thread...
1994 ford f-150 5.8 E4OD obviously with OBD I
I was checking some codes with engine running. I believe these are the KOEO codes. This is a very strange combonation to me. I can't seem to connect them. It might help if I knew what they meant...
Anyway, it threw me a 173, 538, 536, 632.
173 - HEGO sensor circuit indicates system rich (right side)
538 - Insufficient RPM change during KOER dynamic response test/ operator error
536 - Brake on/off circuit failure/ switch not activated during KOER test
632 - Overdrive cancel switch not changing state (E4OD)
I'm still unsure as to what the HEGO sensor is. I'm also unsure how there could be operator error (I didn't touch anything). I don't know what the brake thing is. Overdrive cancel switch? I don't know what that means.
In conclusion, I'm clueless as to what the truck is trying to tell me. If there are any brilliant translators out there, help!
Thanks all for your patience.
Ryan
1994 ford f-150 5.8 E4OD obviously with OBD I
I was checking some codes with engine running. I believe these are the KOEO codes. This is a very strange combonation to me. I can't seem to connect them. It might help if I knew what they meant...
Anyway, it threw me a 173, 538, 536, 632.
173 - HEGO sensor circuit indicates system rich (right side)
538 - Insufficient RPM change during KOER dynamic response test/ operator error
536 - Brake on/off circuit failure/ switch not activated during KOER test
632 - Overdrive cancel switch not changing state (E4OD)
I'm still unsure as to what the HEGO sensor is. I'm also unsure how there could be operator error (I didn't touch anything). I don't know what the brake thing is. Overdrive cancel switch? I don't know what that means.
In conclusion, I'm clueless as to what the truck is trying to tell me. If there are any brilliant translators out there, help!
Thanks all for your patience.
Ryan
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Joined: Mar 2005
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While doing the test at certain points, I forget when but you have to press the brakes and then turn the steering wheel 1/2 turn and then turn on and off the overdrive cancel button and press the pedal down for a wide open throttle check ( just real quick). Not sure on the HEGO someone else will probally help out soon. Good Luck
Edit: Heated Exahuast Gas Oxygen Sensor
Guy in the previous thread had a 173 also and just looked at it and the Ford manual is saying a lot of different things but the pcv and the oxygen sensor I would change the o2 sensor if you haven't in the last 50,000 miles
Edit: Heated Exahuast Gas Oxygen Sensor
Guy in the previous thread had a 173 also and just looked at it and the Ford manual is saying a lot of different things but the pcv and the oxygen sensor I would change the o2 sensor if you haven't in the last 50,000 miles
Last edited by lmooreF250; Apr 27, 2005 at 06:50 PM.
Thread Starter
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Postmaster
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From: Pleasant Hill, MO
okay, I understand the difference between KOEO and KOER. I'm thinking maybe it's my O2 sensor.
To anyone who's had this code: What's the general concensus of what the problem is when a 173 comes up?
Ryan
To anyone who's had this code: What's the general concensus of what the problem is when a 173 comes up?
Ryan
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Joined: Sep 2004
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When running a KOER test, wait for the 4 pulses (or 3 for an I6). Then step on the brake pedal, turn the wheel left and right a couple times, and cycle the O/D cancel switch if you have one.
After about 1 minute, there will be a single flash. This is your cue to briefly stomp the gas pedal and release. The computer will then complete the test.
If you do the above, you will cure all but the code 173.
For code 173, the oxygen sensor is always showing a positive voltage, no matter how hard the computer tries to lean the mixture. The oxygen sensor is not dead or electrically disconnected. It might be so dirty that the exhaust can't get to it.
It is possible the oxygen sensor is giving a false indication, maybe due to accumulation of carbon. More likely is the engine really is running too rich. Check your fuel pressure, especially rate of bleed down after the fuel pump cycles off. A failed fuel pressure regulator diaphragem will dump raw gas into the vacuum line, and from there into the engine.
If you correct code 173, remember to disconnect the battey for 5 minutes so the compute re-learns mixture control strategy.
After about 1 minute, there will be a single flash. This is your cue to briefly stomp the gas pedal and release. The computer will then complete the test.
If you do the above, you will cure all but the code 173.
For code 173, the oxygen sensor is always showing a positive voltage, no matter how hard the computer tries to lean the mixture. The oxygen sensor is not dead or electrically disconnected. It might be so dirty that the exhaust can't get to it.
It is possible the oxygen sensor is giving a false indication, maybe due to accumulation of carbon. More likely is the engine really is running too rich. Check your fuel pressure, especially rate of bleed down after the fuel pump cycles off. A failed fuel pressure regulator diaphragem will dump raw gas into the vacuum line, and from there into the engine.
If you correct code 173, remember to disconnect the battey for 5 minutes so the compute re-learns mixture control strategy.
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Postmaster
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From: Pleasant Hill, MO
I'm not sure I have the equipment to check fuel pressure. I can assure you the engine is running too rich. I can smell the exhaust on the way out, and it's pretty dark.
Where is the HEGO sensor located? Is there a way to clean it without replacing it?
Thanks everyone
Ryan
Where is the HEGO sensor located? Is there a way to clean it without replacing it?
Thanks everyone
Ryan
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From: Bonita Springs FL
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On my 88 5.8 i had a persistant rich code.
Changed O2 but that didn't help.
Wound up being the fuel pressure reg., it hadn't had a hard failure of the diaphram though. It just liked to keep the PSI too high.
What really stinks is you can see it, it's right there, 3 little screws, how long can it take?
Changed O2 but that didn't help.
Wound up being the fuel pressure reg., it hadn't had a hard failure of the diaphram though. It just liked to keep the PSI too high.
What really stinks is you can see it, it's right there, 3 little screws, how long can it take?
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