Working through error codes

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Mar 30, 2022 | 02:25 PM

#16

coneheads

Thread Starter

Cross-Country

Joined: Oct 2021

Posts: 76

Likes: 5

Re-Did the KOER test, the only thing I did is spray the inside of the throttle body and air horn with carb cleaner. The only code that came up this time was 538
Insufficient RPM change during dynamic response test. Sounds like it's still pointing to the TPS?

Mar 30, 2022 | 02:38 PM

#17

rla2005

Fleet Owner

Joined: Oct 2005

Posts: 20,789

Likes: 1,753

From: Kentucky

A brief snap of the throttle during the KOER tests may not be sufficient, you need a good solid Wide Open Throttle (WOT) then release. This has to be done at the correct time and a good solid foot on the throttle. Do not over rev of course but you should see the tach climb well beyond 2000 RPM. I usually go to ~4500RPM.

According to my Ford diagnostic manual if you did do the Goose test at the right time and the RPMs did rise sufficiently the suggested fix is a replacement computer (PCM). I highly doubt that is going to be necessary.

Mar 30, 2022 | 04:04 PM

#18

coneheads

Thread Starter

Cross-Country

Joined: Oct 2021

Posts: 76

Likes: 5

I guess the extension cable for the code reader would help too, the manual says press the accelerator quickly after the reader displays a 10 after the number of cylinders is displayed. I'm not planning on replacing anything until I'm sure it needs it.

Mar 30, 2022 | 04:12 PM

#19

sandymane

Lead Driver

Joined: Oct 2016

Posts: 6,185

Likes: 633

From: Houston/Sugar Land

Yes the extension is a nice feature to have, or have someone watch the reader while you sit in the truck waiting for them to tell you when to do it. Quickly in the test means as when you press the gas and then to let up. As Randy said you do need to get the RPMs up to test properly. I feel good that what he said is the cause of your code but you must recheck it.