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ok guys i have a 89 f250 with the 351... pulled codes, quick question, is it only 2 digit codes, 3 dogit, or can it be mixed.... what i think it came to be is what i post below
KOEO 31
CM 18, 31
KOER 41. 31, 18, 77
asking for some help from the experts here as to where to look at clearing these codes
Last edited by wickedklown83; Jul 6, 2010 at 08:19 PM.
Reason: re-ran test, proper numbers
code 31 is egr positioner sensor below minimum voltage
code 18 is ignition diagnostic monitor (IDM) circuit failure
code 41 is oxygen sensor circuit indicates system always lean
code 77 is brief wide open throttle not sensed during test
code 31 is egr positioner sensor below minimum voltage ----> Check the signal out of the EVP sensor mounted on top of the EGR valve. This code indicates the feedback signal is below .67 VDC when the valve is closed. A collapsed EGR spring or weak diaphragm can cause this as well as an open signal wire.
code 18 is ignition diagnostic monitor (IDM) circuit failure ----> Indicates a problem with the SPOUT circuit or IDM feedback. Verify your SPOUT is securely plugged in and making good contact.
code 41 is oxygen sensor circuit indicates system always lean ----> Indicates the O2 is always indicating a lean reading. Any exhaust leak can cause this issue. Same can be said for a vacuum leak.
Code 41 and 31 could be related if the EGR valve is leaking.
As you indicated DTC 77 was caused by the user during the KOER portion of the tests.