P1800???

1997 4.0 aw4. 212,000mi
No noticeable issues when driving
Check engine light will not reset.
I have not been able to find ANYTHING on this code.
Anyone have any info at all on this???

• P1800 TCM Power Relay Control Circuit

Is it not shifting weird? Perhaps not going into overdrive?

It could possibly not be going into overdrive, only drove it about 15min after the light came on, tcm relay huh, I wonder where to start on that, switch it out with a known good relay? I don't even know where it is, power dist box?

Original_MudButt said:

• P1800 TCM Power Relay Control Circuit

Is it not shifting weird? Perhaps not going into overdrive?

Click to expand...

Where did you find that?

My repair info lists no P1800 for an XJ

I would like to hear the answer as well, I googled all day and found NOTHING!! Also I would like to know where the relay is as a place to start testing.

Digger87xj said:

Where did you find that?

My repair info lists no P1800 for an XJ

Click to expand...

http://www.allpar.com/fix/computer-codes.html

I scrolled right past the heading at the top where it says "2002 and newer". So that may not be it....

I'll call the dealership in the morning, but I'm sure they will say "hey bud, yeah sure, bring it, we can fix that right up for ya. Don't forget, we have financing for ya".......anyone have any ideas? You professional wrench turners, what would you do if this rolled into your bay for diagnostic???

*UPDATE*
Key on/off code retrieval got me Code 12 (battery voltage to PCM disconnected within last 50 key-on cycles) and Code 55(trouble code sequence complete).
My actron ebay scan tool is week!!!!!

Went to autozone an had them scan it, sent a P1898??they refused to clear it. Went to checker, there scan tool wouldn't connect. They will not clear the code however they would let me press the red button, but the scan tool wouldn't connect.
After driving it around I felt absolutely no drive ability issues. I disconnected the batt, cleaned everything up, found no issues with PCM connections or any bad fuses. Fired it up, the light had reset bc of cleaning the batt connections. No light. Recharged my a/c and now I guess I wait and see if it comes back. I guess? Unless there is something specific I should also look at.

P1800 is a manufacturer specific DTC and you're correct about there being limited information. I don't know that I would rely on the codes pulled through the instrument cluster as that was a limited function for your year and just a bi-directional gauge sweep in subsequent years.

If it were mine, I'd be trying to communicate with a more in-depth scan tool. Is your network, or BUS intact? Can you ping modules such as the TCM and get a response? If not, you may have a PCM or wiring problem taking your network down. Since your XJ runs and drives I'm less suspect of this. If you can communicate on the network, my next step would be to check the TCM fuse. If that is OK, I would then begin checking the TCM and associated wiring for continuity. The TCM in that vintage is in the drivers footwell up against the center console but I could be incorrect on that location. You can then find the 3 large connectors in the engine bay near the trans dipstick. I believe two are grey and one is black but again I could be wrong. A google search of wiring diagrams should direct you. Check for continuity and look for shorts. No continuity between the TCM harness and the solenoids could mean a short in the wiring harness or a bad solenoid or both.

Transmission solenoids of that vintage have a tendency to go and cause problems. They are inexpensive and easy to replace. I believe I paid $65 for all 3. If one of them has shorted internally, I supposed its possible this could be your problem. My OD solenoid lasted 155k before throwing multiple transmission codes.

So, to summarize, check fuses, associated wiring and try to communicate with a scan tool. A good scan tool will be able to access the TCM independent from the PCM and pull more data. I suspect you may have a transmission specific code lurking in there that might be of more help.

Good luck.

where did you get trans solenoids for $65???

That's a lot of great information, thank you.
To summarize with what I have right now: I got the P1800 code from a cheep basic $20 scan tool from eBay, it was unable to clear the code. Key on/off odometer/flashing check engine light, code 12. AutoZone's code scan tool retrieved a Honda specific P1898 code, they refused to clear the code. (its against the LAW....ohhh, isn't everything!!!!!)... Checker's scan tool failed to connect, they would have let me push the red button to clear the code. I bought a can of R134a and went home. After driving it some more and having zero performance issues, I cleaned the batt. connections and poked around the PDC. after that I fired it back up, the light had reset, and I topped off the A/C system witch has developed a very small leak. I believe I have one of two things going on: The light was a fluke tripped by an issue with an older system, never to return. Or it is the first hint of trouble that is going to test my shade tree skills, ether way, I'm good.

four_shot said:

where did you get trans solenoids for $65???

Click to expand...

Right here:

http://www.ebay.com/itm/A340-AW4-TR...Truck-3PC-Shift-TCC-A340E-A340F-/191098398550

Looks like they're even a bit cheaper. I've had mine in for 6 months with no problems or codes.