94 F-150 Code 129
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Cross-Country
Joined: Aug 2007
Posts: 80
Likes: 1
From: Reno, NV
I went out and disconnected the battery. I re ran the test and came up with 412, 536, 538, and 632. I think 536 and 632 are tests that need to be a certain way. My concern are 412, and 538.
Help please?
Help please?
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
The KOER 129:
Engine Running DTC 129 indicates insufficient MAF change during Dynamic Response Test.
Possible causes:
-- Open MAF circuit.
-- Open VPWR circuit to MAF sensor.
-- Open PWR GND circuit to MAF sensor.
-- Open MAF RTN circuit to MAF sensor.
-- MAF circuit shorted to ground.
-- Damaged Powertrain Control Module (PCM).
-- Damaged MAF sensor.
-- Air leak before or after MAF sensor.
-- MAF sensor disconnected.
-- Idle Air Control (IAC) system failure (at closed throttle position).
Engine Running DTC 129 indicates insufficient MAF change during Dynamic Response Test.
Possible causes:
-- Open MAF circuit.
-- Open VPWR circuit to MAF sensor.
-- Open PWR GND circuit to MAF sensor.
-- Open MAF RTN circuit to MAF sensor.
-- MAF circuit shorted to ground.
-- Damaged Powertrain Control Module (PCM).
-- Damaged MAF sensor.
-- Air leak before or after MAF sensor.
-- MAF sensor disconnected.
-- Idle Air Control (IAC) system failure (at closed throttle position).
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
DTC 412 indicates that during Engine Running Self-Test, engine rpm could not be controlled within the Self-Test upper limit band.
Possible causes:
-- Open or shorted circuit.
-- Throttle linkage binding.
-- Improper idle airflow set.
-- IAC solenoid contamination.
-- Items external to Idle Air Control system that could affect engine rpm.
-- Damaged IAC solenoid.
-- Damaged Powertrain Control Module (PCM).
DIAGNOSTIC TROUBLE CODE (DTC) 538: SYSTEM FAILED TO RECOGNIZE BRIEF WOT
NOTE:
A brief snap of the throttle may not be sufficient to pass this test. Be sure to go to WOT and return.
Rerun Engine Running Self-Test. Be sure operator is familiar with the Engine Running format which proceeds as follows:
-- Activate Engine Running Self-Test.
-- Start engine.
-- ID Code start of test.
-- Dynamic Response code 1 (0); perform brief WOT.
-- Testing over.
-- DTC output begins.
Possible causes:
-- Open or shorted circuit.
-- Throttle linkage binding.
-- Improper idle airflow set.
-- IAC solenoid contamination.
-- Items external to Idle Air Control system that could affect engine rpm.
-- Damaged IAC solenoid.
-- Damaged Powertrain Control Module (PCM).
DIAGNOSTIC TROUBLE CODE (DTC) 538: SYSTEM FAILED TO RECOGNIZE BRIEF WOT
NOTE:
A brief snap of the throttle may not be sufficient to pass this test. Be sure to go to WOT and return.
Rerun Engine Running Self-Test. Be sure operator is familiar with the Engine Running format which proceeds as follows:
-- Activate Engine Running Self-Test.
-- Start engine.
-- ID Code start of test.
-- Dynamic Response code 1 (0); perform brief WOT.
-- Testing over.
-- DTC output begins.
Thread Starter
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Cross-Country
Joined: Aug 2007
Posts: 80
Likes: 1
From: Reno, NV
After reading my Autoxray book I think most of my problems are from doing a KOER. Instead I should be doing a KOEO, and look for stored codes. I love my Ford trucks, but GM's OBD1 kicks butt over this.
Fleet Owner
Joined: Aug 2005
Posts: 23,666
Likes: 301
From: Easton,Ks
The KOEO test is basically an electrical test of the sensors and relays (hard codes).
You have to pass the KOEO test first or the KOER tests does not mean anything.
Next comes the CM (stored codes) read out of things that happen while driving and such.
Then you do the KOER tests and thet test is basically a test for the solenoids and relay outputs.
You can also do an solenoid on test after the CM readout.
Then after all of that you can do the engine balance test to see if all of the injectors are working the same and all the plugs are working with balanced compression.
You can do all of this without an Autoxray.
You have to pass the KOEO test first or the KOER tests does not mean anything.
Next comes the CM (stored codes) read out of things that happen while driving and such.
Then you do the KOER tests and thet test is basically a test for the solenoids and relay outputs.
You can also do an solenoid on test after the CM readout.
Then after all of that you can do the engine balance test to see if all of the injectors are working the same and all the plugs are working with balanced compression.
You can do all of this without an Autoxray.
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