QuestionQUESTION: I have read some of your other threads Roland and I am shocked that some other individuals have had this exact same issue.
Right now the car is in limp mode with the engine light on and the following codes p1684 p0700 and p0605. The last number was found by AutoZone.
The car had this same issue about 3 days ago and after driving for a little while we stopped the car and restarted it. The car started shifting and the engine light went off.
(Just as the previous person mentioned) Three weeks ago the speedometer stopped working and subsequently started working again prior to these transmission issues.
I replaced both the input/output speed sensors and the car is still in limp mode.
I wonder why the car was able to recover from the problem the first time. It makes me think there is some sort of electrical fault vs. an actual part failure.
I have it at the dealer right now and they should be getting back to me shortly. I plan on asking them for the DRB III error codes from the Transmission Controller, but I wanted to see what your thoughts on this are.
FYI, I also tried to wire the 37, 80 relays together to bypass the limp mode like you mentioned but that didn't work. It still was stuck in 'limp mode' or 2nd gear.
ANSWER: Hi Leonard,
The 1684 is quite common and means that the battery power to the engine controller was disconnected sometime in the past 50-100 key on-off cycles. Unless that didn't happen it can be ignored. It might have happened in order to erase the fault codes for example.
The 0700 alerts you to there being a transmission fault code also present
And the important one is the 0605 which says that the transmission control module function is impaired (had internal errors). The instruction is to inspect the wiring harnesses and plugs to the transmission and if those prove unremarkable then the fix is to replace the transmission control module, which is not a major labor issue, but rather a cost of part issue and doing a tranmission quick learn procedure using the DRB III.
So see how that compares to what the dealer shop says. The relay by-pass of course will not always work to get you by temporarily if the balance of the module is bad at the same time.
The temporary recovery could have been just the fact that the module was in the process of going bad at the time, if it indeed proves to be the issue now.
Roland
PS: May I ask a favor? If you will be so kind as to click on the "Thank/rate the expert" button below left it will take you to a page for numerical rating of my answer and also to ask you whether you wish to nominate me to be 'volunteer of the month' at the Allexperts site. I am in close competition for that recognition and so can use all the nominations I can get. So please give my a "yes" to that question if you feel I warrant it.
Many thanks for doing that.
---------- FOLLOW-UP ----------
QUESTION: Dealer said that they are getting the 0605 code and that is as far as they can get. The also said that the TCM would have to be replaced. Repairs are quoted at:
Part: $329
Labor: $170
How likely is it that replacing the TCM will fix the problem? Also, how can I verify that the part was replaced and it wasn't simple a connection problem? Can you provide a schematic on where the TCM is located?
AnswerHi Leonard,
The tcm is located 'behind' the left fender (meaning you will see it on frame rail that is seen if you turn the steering wheel far left, look in front of the tire and behind it to see the rail) fastened by 3 screws to 3 clips in the chassis frame rail, forward of the suspension. You will see the 2 harnesses/plugs connected to it and can trace them to the transmission, one large one small plug and inspect them for damage yourself. Absent any signs I would believe the tcm is bad, To thorougly check the wires electrically is a big job, so absent physical damage one has to assume the wiring/plugs are OK. In my state the shop is supposed to give you the bad part that it has replaced, so you could verify the part number that is given you to be the same as the part you paid for.
If you don't trust the dealer you might do some comparison shopping for the part over the internet, or try some independent repair shop to do the job. It is really plug and play, except the new one needs to learn the particular characteristics of the transmission which you can accomplish with a little bit of road acceleration/decelearation manoeuvers which I can tell you about or pay the shop with the right tool to do it "quickly". The trans controller does learn on it own too. I suspect you can do it yourself and save the labor, and also get the part cheaper with a little bit of 'shopping'.
Roland
PS Many thanks for the earlier nomination and you are entitled to do it again if you so choose. I would of course be pleased if you do so.
