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1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

Diagnosing the problem

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Old Mar 4, 2018 | 10:43 PM
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James Powell
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Diagnosing the problem

So I just finished the koeo and koer test and the results of the engine off test was two codes 51 and 52. My question is about the engine running test. First I did the pre test warm up of my truck which is an 88 f150 302 4x4 auto by the way but when I started the test the cell flashed 9 times then flashed 8 time then a brief pause followed by 5 flashes and another single flash. The cell ran trough this sequence twice then without me touching the throttle the truck kinda revved up all by its self... after this happens the cel light goes off for a moment or two then comes back on indefinitely. Can anyone shed some light on my issues?
 
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Old Mar 5, 2018 | 07:48 AM
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KOEO Codes:

Code 51: ECT sensor signal is greater than the Self-Test maximum of 4.6 volts.
Code 52: Power steering pressure switch always open or closed.


KOER Codes:

Code 98: Hard fault present.
Code 51: ECT sensor signal is greater than the Self-Test maximum of 4.6 volts. (not 100% sure that can appear as a KOER code, but makes sense if it did)

Based on Code 51 in both sets of tests and the Hard Fault code I would test the ECT sensor. Replace it if it is bad.

For reference: Engine Coolant Temperature sensor
 
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