P1646 & P1647

[evralive]

Hello,

Ive had problems with my 2002 Toyota mrs SMT since I bought it.

The Engine management light is always on and I'm getting the following errors: P1646 & P1647

Now when I first bought this car it had all the gears except reverse. Although the gears seemed a bit messed up, first seemed like second, second like third and so on.

After 3 days of owning the car it broke down, wouldn't start up or anything. I took it to a toyota dealer in lincoln and they told me it was the gearbox. I managed to replace the gearbox myself, although I got to a point were I was told I needed a special tool to align the gears to put this box back onto the gearbox. I didn't want to waste any more money so I moved it around with my fingers and slotted it into place. After replacing the gearbox I tried starting the car to only find the car has no gears at all..

With a little fiddling I managed to get the car started but the car only has 2nd,3rd,4th and 5th. I drove the car for 10 minutes just to give it a run to see if it would then find 1st and reverse (which it has not).

I bought an ECU reader and got the following codes from the car P1646 & P1647.

I tried resetting the codes just incase the ecu had remembered them from the previous gearbox (i only found the codes out today and what they mean). this of course hasn't done anything.

I googled the codes and found that the ECU transmission has a fault or bad connection?

I'm writing to see if anyone has any guidance for me? I don't want to replace the Transmission ECU if this isnt the problem and waste more money.

Does anyone know where I could find the Transmission ECU to check the wiring? I've looked everywhere but can't seem to find it.

I also found quite alot of wiring down the doors that seemed to be ducktaped together (which is really bad, and i've fixed).

If anyone could help me out I'd be very grateful, I havent been able to drive this car since I bought it 6 months ago and I've already wasted a years worth of insurance, tax and MOT! along with brand new gearbox. I simply cannot afford to waste any more money.

All the best,

Simon

[evralive]

I spoke to an expert at justanswer.com and he gave me the information below along with this diagram:

http://www.justanswer.com/view_image.aspx?href=http://ww2.justanswer.com/uploads/djenn434/2011-05-01_141809_tcm_0000.jpg

P1646 Transmission Control ECU Malfunction

Possible Causes Setting Conditions

Communication data bus circuit is open or shorted to ground

Communication data bus circuit is shorted to voltage

Transmission Control ECU has failed (no communication fault)

Key on or engine running; and the PCM did not detect any signals from the Transmission Control ECU for 3 seconds.

This code sets in 1 Trip(s).

This code will turn on the MIL (Malfunction Indicator Lamp)

P1647 CAN Communication Malfunction

Possible Causes Setting Conditions

Communication data bus circuit is open or shorted to ground

Communication data bus circuit is shorted to voltage

Transmission Control ECU has failed (no communication fault)

Key on or engine running; and the TCM did not detect any signals from the Engine Control ECU for 3 seconds.

This code sets in 1 Trip(s).

This code will turn on the MIL (Malfunction Indicator Lamp)

"If the gearbox was bad it shouldnt cause these codes but if the ecu was bad it could cause shifting issues so I'd start by testing data wire and replacing transmission control module if needed. If problem is still there then gearbox will need to be repaired or replaced. Let me know if you have questions, thanks."

"Its is a blue orange wire that goes from terminal 85 of transmission control module to 30 of engine control module. Here is a picture location of module.(see diagram)"

Hope this helps people with my problem in the future, if anyone else can help please reply.

[Emmanuel Hangumba]

On 5/1/2011 at 5:10 PM, evralive said:

I spoke to an expert at justanswer.com and he gave me the information below along with this diagram:

http://www.justanswer.com/view_image.aspx?href=http://ww2.justanswer.com/uploads/djenn434/2011-05-01_141809_tcm_0000.jpg

P1646 Transmission Control ECU Malfunction

Possible Causes Setting Conditions

Communication data bus circuit is open or shorted to ground

Communication data bus circuit is shorted to voltage

Transmission Control ECU has failed (no communication fault)

Key on or engine running; and the PCM did not detect any signals from the Transmission Control ECU for 3 seconds.

This code sets in 1 Trip(s).

This code will turn on the MIL (Malfunction Indicator Lamp)

P1647 CAN Communication Malfunction

Possible Causes Setting Conditions

Communication data bus circuit is open or shorted to ground

Communication data bus circuit is shorted to voltage

Transmission Control ECU has failed (no communication fault)

Key on or engine running; and the TCM did not detect any signals from the Engine Control ECU for 3 seconds.

This code sets in 1 Trip(s).

This code will turn on the MIL (Malfunction Indicator Lamp)

"If the gearbox was bad it shouldnt cause these codes but if the ecu was bad it could cause shifting issues so I'd start by testing data wire and replacing transmission control module if needed. If problem is still there then gearbox will need to be repaired or replaced. Let me know if you have questions, thanks."

"Its is a blue orange wire that goes from terminal 85 of transmission control module to 30 of engine control module. Here is a picture location of module.(see diagram)"

Hope this helps people with my problem in the future, if anyone else can help please reply.

Even me this is the problem its is giving me please i need help