2003 C230, p0135, Electrical Issues
Thread Starter
Super Member
Joined: Oct 2007
Posts: 537
Likes: 2
From: Charlotte, NC
2013 S550, CLS500, ‘03 SL500, “92 190E Sportline
2003 C230, p0135, Electrical Issues
I have a 2003 C230 Sedan (m271 engine) 135k miles.
I've had a p0135 code for months, with bad gas mileage. (I can barely get 25mpg highway, where I used to get 30+)
p0135 Code: 02 Sensor Heater Circuit Malfunction, Bank 1, Sensor 1
I replaced the 02 sensor with a Denso direct fit sensor, code did not clear. I replaced that sensor with a Bosch Dealer sensor, code did not clear, gas mileage still bad.
If I clear the code with a scan tool, with the car on, the code will stay off while driving. However, if i shut the car off and restart it, the CEL instantly comes back on as soon as I start it up.
I replaced the alternator and voltage regulator, thinking the regulator may have been the culprit, but still nothing has changed.
I've also recently changed the MAF Sensor, spark plugs & Ignition coils, and serpentine belt.
Anyone else have a problem similar to this? Also around the same time, my headlamp washer's stopped working, passenger seat motor became inoperative, and the SRS light is on (passenger side occupant sensor).
Would I possibly need a new wiring harness? I did fix the cam sensors a while back with MB's isolating wires & new cam sensors.
Any help would be appreciated, thanks!
I've had a p0135 code for months, with bad gas mileage. (I can barely get 25mpg highway, where I used to get 30+)
p0135 Code: 02 Sensor Heater Circuit Malfunction, Bank 1, Sensor 1
I replaced the 02 sensor with a Denso direct fit sensor, code did not clear. I replaced that sensor with a Bosch Dealer sensor, code did not clear, gas mileage still bad.
If I clear the code with a scan tool, with the car on, the code will stay off while driving. However, if i shut the car off and restart it, the CEL instantly comes back on as soon as I start it up.
I replaced the alternator and voltage regulator, thinking the regulator may have been the culprit, but still nothing has changed.
I've also recently changed the MAF Sensor, spark plugs & Ignition coils, and serpentine belt.Anyone else have a problem similar to this? Also around the same time, my headlamp washer's stopped working, passenger seat motor became inoperative, and the SRS light is on (passenger side occupant sensor).
Would I possibly need a new wiring harness? I did fix the cam sensors a while back with MB's isolating wires & new cam sensors.
Any help would be appreciated, thanks!
Last edited by aolsen; Feb 27, 2011 at 07:03 PM.
Thread Starter
Super Member
Joined: Oct 2007
Posts: 537
Likes: 2
From: Charlotte, NC
2013 S550, CLS500, ‘03 SL500, “92 190E Sportline
Thread Starter
Super Member
Joined: Oct 2007
Posts: 537
Likes: 2
From: Charlotte, NC
2013 S550, CLS500, ‘03 SL500, “92 190E Sportline
Sorry for the late reply. Yea I had that done. When the hose issue occurred my car shook violently and had very poor gas mileage and threw multiple codes. Now my issue is one constant p0135 code, and poor gas mileage. The car shakes sometimes for about 30 seconds after startup, then idles fine.
