97 E320 in Limp mode
 

Trying to pass my father 1997 E320 to my son as his first car. The car sat for a long while with minimal use. The car has about 100K on it.

The issue is that the car is in limp mode and can not exceed ~35mph. The instrument cluster is functional with the exception of the the speedometer.

Getting a warning light for ETS and ABS on the cluster. Pulling the codes I saw that the left rear ABS sensor was defective - that has been replaced.

I disconnected the plug on the transmission and found lots of ATF. I cleaned the chassis side of the plug and replaced the plug housing. The car was suffering from limp mode still. ETS and ABS lights where still on

I next replaced the sensor plate in the transmission - still in limp mode with the same lights on the cluster.

Tested all fuses in the various fuse boxes found all where good

Getting the following errors - that will not clear

B1041 Fault in CAN Communication with control unit traction systems
P1605 Rough road detection signal by comparing wheel speeds
P0600 No or Incorrect CAN message from control unit ESP
P1747 CAN Fault

Where should I be looking next

You are doing it the right way by pulling codes. Is the charging voltage good/voltage regulator problem??? My '93 300E went into limp mode several times, it was the brake lamp switch each time.

Good luck!!!

If your electrical plug on the tranny was full of fluid, your TCM is probably contaminated with fluid. Pull the plugs off of the TCM. if there's signs of fluid then remove the TCM, remove the cover, let it drain and clean. That can cause limp mode. Even with no faults in the TCM. And, by limp mode, I assume you mean that it's stuck in 2ng gear.

thanks - the tcm is located on the passenger side engine compartment correct?

do you have a scan tool that can communicate with the car from the round 38 pin interface in the engine room fuse box?

This model of mercedes is unique as it wont let go of the transmission limp mode unless you command it to reset, which can only be done by specific tools that can connect to the 38 pin port and then talk to the TCU. This car wont reset the TCU itself if everything reports ok.

same with ABS faults. If you dont see any speedo input then you need to interrogate that unit too, which again is only accessible from that round 38 pin port.

yes, its in that box with all the other control units.

I have a foxwell nt530 loaded up with the MB software and using a 38 pin connector. When I try to talk to the transmission module it fails

Did you check your TCM for fluid contamination? If it is, the system won't communicate. It's like it's not even there. I have a w210 e55 in the shop right now that won't communicate with the ECM. It turns out it's contaminated with water.

remove the tcu and pull out the circuit board, then flood it clean with contact cleaner. You have to remove all the oil residue from it and retry when its fully dry.

work and weather have been in the way - planning to do so tomorrow - will update with what i find

i pulled the tcm - looks to be dry on both the connectors and plugs (to the tcm) - it is in the low 30's out so brought it in to warm up before i try to pull the case apart.


edit I got it pull apart it is bone dry

Now is the time to get hold of an oscope and check if the TCM is on the can bus. You will also need to find if there is 5V reference to the speed sensors in the transmission. If you have 5V reference then the TCU is on and you have a communications message fault. btw - the shifter is part of the bus network too.

is there somewhere i can read how to do that