Swapping out ECM and ignition key (and transponder) question (1 Viewer)

Joined
May 26, 2016
Messages
59
Location
Klein, TX
Quick summary of my issue.

- bought my '99 from a guy (PO #3) who bought it from another guy (PO #2) who bought it from another guy (PO #1)
- PO# 3 sold me the car after owning it for about 2 weeks and in that time said he had a new key made and put in a brand new battery
- I got the car and after 3 days it would crank but would not start
- Had a locksmith out and flashed the ECU and made another key. The car ran for about 2 weeks and did the same thing -- it cranks but won't start.
- I had it towed to the dealership and they said they would need a locksmith flash the ECU. That would be $1400. I said no because I think I would run into the same problem again because in 5 weeks two keys were made and the ECM flashed twice.

While researching this issue I found out that PO #2 rolled back the odometer from 300K to 139k miles. Don't know how he did it but the odometer reads 139K but I talked to PO #1 and he said the truck has 300K miles. I suspect something is messed up when all this happened and I just want to fix the problem once and for all so I can use the truck. I am thinking of buying another ECM (product number 89661-60610) with the ignition switch and key to replace mine. Does anyone know for certain if this will work? I need a definitive answer before I go this route.
 

duggy

SILVER Star
Joined
Aug 15, 2011
Messages
2,646
Location
Houston, Texas
Also check your crank sensor wiring. If not routed properly after a timing belt job, the serpentine belt can chafe the wiring and cause you not to start your vehicle
 
Joined
May 14, 2016
Messages
119
Location
Metro Detroit Michigan USA
Were you informed of the actual mileage before the purchase?

If not I would demand a refund and buy a another 100.

Seems like trouble to me if you ever decide to sell it or anything else...
 
Joined
May 26, 2016
Messages
59
Location
Klein, TX
Were you informed of the actual mileage before the purchase?

If not I would demand a refund and buy a another 100.

Seems like trouble to me if you ever decide to sell it or anything else...

It's my stupidity for not running a carfax so as Dave Ramsey would say, I am paying the stupid tax. But I learned my lesson from this experience. So now I am just trying to get this running and move on.
 
Joined
May 26, 2016
Messages
59
Location
Klein, TX
Also check your crank sensor wiring. If not routed properly after a timing belt job, the serpentine belt can chafe the wiring and cause you not to start your vehicle

Hey Duggy, you may have seen my posts on Facebook in the LC groups. At this point I am 99% sure it's the stupid immobilizer/transponder not working for some reason. I took it to the dealership to confirm the issue and that's what they told me. But they want $1400 to call in a locksmith to flash the ECU. But we've already done that twice and it only runs for a few weeks. The service manager said you get 20 starts before the immobilizer disables the car if it doesn't recognize the key.
 
Joined
Dec 19, 2015
Messages
1,386
Location
United Kingdom
If you type "Fix for immobiliser issue" into the search you will find a lot of info on this issue, a 30 amp fuse is a temporary fix as it seems there are issues with the fuse box. It might not be this but it does seem to be the most common issue with the immobiliser.
 
Joined
Jun 21, 2005
Messages
596
Location
Apex, NC
Your locksmith probably has the ability to read the EEPROM chip in the ECU when he flashes it. Each of your keys is stored in there using an 8-bit hex code. Have him flash it again, but note the codes that are in there before and compare to after. They should be the same, or the same 2-digit pairs will be there but on different rows (if the keys are programmed in a different sequence than the last time.) In either case, your ECU is good because your keys are still stored, and it's probably your transponder amplifier or just resetting during the 30 minutes your battery is disconnected.

If the codes aren't similar, then your EEPROM chip is somehow getting corrupted and a new ECU might fix your issue. I doubt that's the case, but if it is, grab one off of car-part.com for $100-200. The updated part # is 89661-60611.
 

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