Renault Scenic 2.0 2001 - Transmission in limp, code DF048 #
Posted by Alan Kane on February 28, 2011, 4:16 pm
Year of Manufacture *: 2001
Renault Scenic Vin - VF1JA0C225134791 Year - 2001 2.0 petrol auto. Scantool - Renault Clip
Fault symptom according to the customer – trans won’t change gear occasionally with the trans lights lit. If it drives right, its perfect.
Customer – is the type who “just wants it fixed” and doesn’t want to even answer basic questions.
History – I looked at this car 2 months ago for the same fault. I found the car cranked slowly due to a low battery, but then started. After being run it cranked and ran normally. Battery charged and tested ok. Customer said it hadn’t been lying up or given trouble starting ever, but later changed her mind. So I think it was lying up for about two weeks and might have been slow to start at least once before I saw it. I mention this because a couple of days later it was slow to crank and dropped into limp again. It appeared that the slow crank and trans limp were connected. So that leads to my first question, is it common for the trans on these to drop into limp due to low system voltage?
Fault symptom noted by me – I collected the car. Trans not in limp but didn’t pick up the gears like it should. Slow to change up. No flareing but a little rough on the downshift.
Testing – Code read. Auto ecu - DF055, injection-auto trans connection. DF048 vehicle speed information (2DEF). DF131 slip. No codes in any other modules. Checked the codes in Dialogys. No real help there but would suggest CAN error or road speed signal missing. I cleared the codes and drove it. It was not in limp any more but still not right. As above, not picking up the gears right. I reset the adaptions and drove it again. It drove pretty much perfect. I couldn’t find any fault with it. Checked wiring and ecu connections, all ok. The customer didn’t need it back in a hurry so I kept it a few days and used it myself. The fault didn’t happen again, no fault codes returned, so I assumed it was due to low voltage and gave the car back.
After being ok for 2 months it has happened again. It seems the symptom is the same but I haven’t seen it give trouble. Code read. Auto trans ecu - DF048 (DEF3). No codes in any other modules.
If low voltage would cause this maybe a bad battery even though it tests ok? I will probably recommend a new battery.
Lack of road speed signal could cause this or maybe DF048 is a red herring. I will update the trans ecu software. There is no option to update the ABS.
These do suffer with broken wires on the speed signal. Check the archives, but the ones I've had have all been about a foot from the multiplug on the n/s inner wing.
This fault is usually acompanied with loss of speedo, so it might be worth probing the customer more.
The fault code DF048 with (3.DEF), according to CLIP, is a “multiplex error” so I assumed it was a signal missing from the CAN but if the CAN was down I would have expected a lot more codes. This was the only code in the whole car.
Maybe in Renault terminology a dedicated speed signal wire from one ecu to another is “multiplex”. I will check for that later today and open the loom in the area you suggested.
Limited time today and the customer wanted the car back.
I have opened the looms and found no damage. I can trace the grey wheel speed wire from the ABS to the near side under the fuse box. From here it goes under the arch and looks to go inside the car. As far as I can see this speed signal does not go directly to the trans ecu. There was no continuity between the grey wire and any trans ecu multiplug pin while the fault was not present. It looks to me like it is a missing CAN signal. Looking at diagrams on dialogys is not easy. If I was looking at the right info then that would back up my thoughts that it is a CAN signal. When I get more time I am going to try and identify the correct diagrams. For DF048 Dialogys suggests checking the wheel speed signals in the ABS and then the network. Again, sounds like a CAN signal to me.
I have warned the customer that if it happens again, as I expect it will, I will need the car longer. I will update when I get the inevitable phone call.
In the meantime, if anyone knows how the speed signal is routed I would be interested to hear it.