Engine Computer Issues? - JeepForum.com
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post #1 of 5 Old 04-23-2021, 09:44 PM Thread Starter
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Engine Computer Issues?

I just picked up a low mileage 2008 Jeep JK. It ran and drove excellent. All was operating perfectly. Being the OCD person that I am, I decided the never-cleaned engine compartment has to be addressed. As I have all my vehicles, I sprayed it down in simple green and took the power washer to it. It looked fantastic when finished. I used my compressor to dry all connector (exterior of connectors) and started the engine. It ran perfectly. I let it run until warm to continue to dry all components and then shut if off. When I started it the next day the check engine light came on. I drove it in to town, figuring that the CEL was engine wash related. It seemed to run fine. I do remember on the downhill to our house that there was impressive engine braking, but had the radio on and maybe did not notice high RPMs. The next morning I started to again drive the Jeep but quickly found that RPM were 4,000 at 45 mph. I realized something was wrong and doubled back to the house. Later, I again test drove (CEL still lit) and the (auto) transmission will not shift out of what appears to be 1st gear. After some reading, I determined that water may have compromised the harness connectors going into the computer module. I (with the battery connected) systematically removed each connector, blew each side with compressed air and reconnected. I did the same for the two connectors behind the intake manifold. I also disconnected the battery and reconnected. Now when I start the engine I get the CEL, the electric bolt symbol and the traction control symbol and the engine runs rough, stumbles and will not accelerate.

I must also add that I have also made numerous attempts to scan with an ODB II and the scanner comes up with ERR.

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post #2 of 5 Old 04-24-2021, 08:05 AM
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2014 JK Wrangler 
Join Date: Oct 2017
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I suggest a different scanner, or tell us if you have a quality (read $$$) scanner?

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 5 Old 04-24-2021, 12:33 PM Thread Starter
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No, it was a generic, low cost reader. I used to have a Hypertech tuner that I used for this purpose, but sold it with my last JK.
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post #4 of 5 Old 04-24-2021, 03:11 PM
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2009 JK Wrangler 
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Location: Lakewood
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I (with the battery connected) systematically removed each connector
Not a good idea. ANY time you do any sort of electrical work on a vehicle, you need to disconnect the battery. If you fried your TIPM, this is what likely did it.

'09 JK Rubicon
'01 XJ Sport
'10 Fusion
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post #5 of 5 Old 05-04-2021, 11:05 PM Thread Starter
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OK, I want to take an opportunity to update this issue.

After cooling my jets for a couple days, I decided to systematically repeat the steps I had previously taken, but with the battery disconnected this time. I disconnected all the wire connectors under the hood and again blew them out with air and reconnected. After completing and about 20 minutes later I connected the battery and connected by newly acquired Superchips 6874. I read the codes as P0882 and cleared the code. After clearing and starting the engine the CEL came back on immediately. I shut off the engine and cycled the ignition key three times at roughly 15 seconds each. This time the CEL did not return and I drove the Jeep to find that it was still operating in 2nd gear. After 30 minutes of driving, it did not set off the CEL. After more research, I learned that the TIPM J18 fuse could be the culprit in not allowing the transmission solenoids to operate. I pulled the 20-A fuse and sure enough, it was failed. I replaced with a new fuse and can report that all is now working perfectly!
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