Borris1954
Active Member
- Joined
- Feb 4, 2013
- Messages
- 414
- Location
- South Bucks
- Car
- S204 C 250 CGI BlueEFFICIENCY, R170 SLK 230, B 180d AMG Line
Hi Fellow Mercedes owners,
I have am having a bit of a nightmare with the rear parking sensors on my fairly recently acquired E320 CDi Estate (a facelift version from December 2006).
I have the usual issue with the two red lights on the displays and sensors not working. Plugging in my iCarsoft i980 OBD fault reader tells me that I have fault code 901B and that there is a problem with A43b9 the inner left rear sensor. It says it's either not connected properly, there's an issue with the wiring or the sensor is faulty. That seemed fairly clear so I purchased a couple of sensors from eBay put one in and tried again. Fault unchanged! Tried the other one and again the fault remained unchanged. Ok I thought - it's possible I have been sent two faulty sensors so I tried them both in place of the rear inner right sensor - no fault for that sensor position showed up so presumably they are OK? Next I put the "faulty" sensor in the rear inner right position hoping the fault would move to that position but yet again the fault remained unchanged at rear inner left! By this time I am getting fed up with grovelling under the car so decided to remove all 4 sensors and the wiring loom so I can investigate more comfortably with everything laid out on the load compartment floor - much much easier but still no joy. I cleaned all the contacts with switch cleaner and "buzzed" the loom through to confirm connectivity which all seemed fine. Maybe it's the connector itself which although it checks out OK with my meter may not be actually connecting properly with the sensor when it's plugged in. So I purchased a second hand loom from an S class (with the same type of connectors) and changed the connector for the rear inner left sensor. Disappointment yet again - fault still unchanged. In desperation I tried another PTS Control unit (A211 545 8932) and pretty much as I expected I am still getting the same fault for the rear inner left. This is getting beyond a joke!
Where to next? Anyone got any suggestions?
The Front sensors seem to work fine providing you haven't selected reverse and thus caused the fault to be actively logged again.
Thoughts I have are:
1) There is a wiring issue somewhere between where the rear bumper loom plugs into another loom socket in the load compartment and the plug that then finally connects the sensors to the PTS control unit - seems unlikely but could just be possible I suppose.
2) The iCarsoft unit is giving me a bum steer on fault location which also seems unlikely but possible.
3) The iCarsoft is also reporting a couple of DTCs that it isn't able to pin down specifically. They are 9027 and 9024. A quick google reveals these are generic codes - the question is are these significant in some way I don't understand
4) I am being an idiot and missed something blindingly obvious somewhere
Any suggestions welcome
Thanks for listening/reading this tale of woe
I have am having a bit of a nightmare with the rear parking sensors on my fairly recently acquired E320 CDi Estate (a facelift version from December 2006).
I have the usual issue with the two red lights on the displays and sensors not working. Plugging in my iCarsoft i980 OBD fault reader tells me that I have fault code 901B and that there is a problem with A43b9 the inner left rear sensor. It says it's either not connected properly, there's an issue with the wiring or the sensor is faulty. That seemed fairly clear so I purchased a couple of sensors from eBay put one in and tried again. Fault unchanged! Tried the other one and again the fault remained unchanged. Ok I thought - it's possible I have been sent two faulty sensors so I tried them both in place of the rear inner right sensor - no fault for that sensor position showed up so presumably they are OK? Next I put the "faulty" sensor in the rear inner right position hoping the fault would move to that position but yet again the fault remained unchanged at rear inner left! By this time I am getting fed up with grovelling under the car so decided to remove all 4 sensors and the wiring loom so I can investigate more comfortably with everything laid out on the load compartment floor - much much easier but still no joy. I cleaned all the contacts with switch cleaner and "buzzed" the loom through to confirm connectivity which all seemed fine. Maybe it's the connector itself which although it checks out OK with my meter may not be actually connecting properly with the sensor when it's plugged in. So I purchased a second hand loom from an S class (with the same type of connectors) and changed the connector for the rear inner left sensor. Disappointment yet again - fault still unchanged. In desperation I tried another PTS Control unit (A211 545 8932) and pretty much as I expected I am still getting the same fault for the rear inner left. This is getting beyond a joke!
Where to next? Anyone got any suggestions?
The Front sensors seem to work fine providing you haven't selected reverse and thus caused the fault to be actively logged again.
Thoughts I have are:
1) There is a wiring issue somewhere between where the rear bumper loom plugs into another loom socket in the load compartment and the plug that then finally connects the sensors to the PTS control unit - seems unlikely but could just be possible I suppose.
2) The iCarsoft unit is giving me a bum steer on fault location which also seems unlikely but possible.
3) The iCarsoft is also reporting a couple of DTCs that it isn't able to pin down specifically. They are 9027 and 9024. A quick google reveals these are generic codes - the question is are these significant in some way I don't understand
4) I am being an idiot and missed something blindingly obvious somewhere
Any suggestions welcome
Thanks for listening/reading this tale of woe
