Author Topic: ECU/TCU/check engine light  (Read 865 times)

bpw

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ECU/TCU/check engine light
« on: December 23, 2018, 01:56:20 PM »
Hi,

1998 Montero 3.5 CA emmisions, non-winter package but I have added a factory locker set-up and control module.

Somewhat odd set of issues and looking for thoughts on things to check as well as info on the TCU/ECU computers.

For the last couple months I have been chasing a check engine light showing code P0400 "EGR A flow" and P1750 Solenoid assembly.  The EGR code has been coming and going for few months while the solenoid error is recent.

My mechanic has gone through the EGR system and can't find any issue with EGR valves or vacuum leaks.  After a reset it often takes 500-1000 miles before it turns on again and it seems to correlate with a drop in the idle speed.

The Solenoid error code started showing after the truck would not shift into overdrive one day.  Restarting the car fixed the overdrive issue and it has not recurred but the code comes back after a reset.

Mechanic says he is not getting good info when he hooks his code reader up and suspects it may be an issue with a flaky ECU or TCU.

I also get a very occasional no start where the engine will not crank and turning the key off and on again fixes the problem, no solenoid click when it happens and starter is strong when it does work.  Most likely unrelated starter issues, but not sure if it could be the security system telling the car not to start.

This make any sense?  Any thoughts?

What years ECU and TCU cross reference?  They are pretty cheap used so I may just get them to try.

Shovel

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Re: ECU/TCU/check engine light
« Reply #1 on: January 02, 2019, 12:14:41 PM »
Engine and transmission computers very rarely fail, and typically when they do it's as a result of another failure (which will kill the new one too if not addressed)

I'd be looking at wiring insulation.   Everywhere.   Getting brittle on these trucks unfortunately. 

bpw

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Re: ECU/TCU/check engine light
« Reply #2 on: January 02, 2019, 03:40:24 PM »
It may have just become moot, truck is 12 miles out a dirt road waiting to be dragged out friday after I had to leave it with a very loose crank pulley/harmonic balancer. 

Not sure the damage yet but I'm not real optimistic since the bolt felt messed up (could move freely 1/4 turn in either direction then jammed) and the pulley was moving around completely free with lots of wiggle.

Hoping the crank nose didn't get screwed up....but I'll start worrying about the check engine light once I confirm I don't need a new motor.

kalieracer

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Re: ECU/TCU/check engine light
« Reply #3 on: January 03, 2019, 11:44:10 PM »
thow a 3.8 long block in there.