[Jackson54]

Hi all, as title states, get a hard fault code at all times even after clearing codes/resetting adaptations. Replaced both pre cat O2 sensors with known good ones and both rear 02's are fairly new. Also checked 30amp fuse in glovebox which was intact. Was after replacing starter when code appeared. Code was not present before starter installation. Could a pinched sensor line running from the junction box under the manifold cause this? What is the best way to test this? Resistance test at sensor pins? Any help greatly appreciated. Code below.

2C9D- DME: Oxygen sensor heater 2 before catalytic converter activation.

[dpaul]

Originally Posted by Jackson54

Hi all, as title states, get a hard fault code at all times even after clearing codes/resetting adaptations. Replaced both pre cat O2 sensors with known good ones and both rear 02's are fairly new. Also checked 30amp fuse in glovebox which was intact. Was after replacing starter when code appeared. Code was not present before starter installation. Could a pinched sensor line running from the junction box under the manifold cause this? What is the best way to test this? Resistance test at sensor pins? Any help greatly appreciated. Code below.

2C9D- DME: Oxygen sensor heater 2 before catalytic converter activation.

Not sure why a starter replacement would impact O2 sensor wiring - at least on my vehicle, the sensors are on the passenger side, opposite side from the starter, and their cables do not run anywhere near the junction box under the starter. Did you replace the starter or was it done at a shop?

It cannot be a problem with fuse F38 because it supplies all four O2 sensor heater, not just pre-cat bank 2.

It is not clear from your description whether you replaced the pre-cat sensors after getting the heater code but assuming you did and the code remains, then yes, a wire/connector fault is the most likely explanation. It is possible that the DME is bad but that is rare. Easy enough to test for voltage on the sensor connector and integrity of the wire back to the DME

Pin4 is positive 12v to heater, pin 3 is return to DME. Voltage test on the DME side of connector (pin 4 and ground), resistance test heater on the sensor side (pins 3 and 4 - should be something like 25 ohms or so). Resistance test the DME wiring between pin 13 on the DME connector and pin 3 of sensor connector. If the wires check out but there is no voltage, worry about your DME.

[Slade_]

Originally Posted by Jackson54

Hi all, as title states, get a hard fault code at all times even after clearing codes/resetting adaptations. Replaced both pre cat O2 sensors with known good ones and both rear 02's are fairly new. Also checked 30amp fuse in glovebox which was intact. Was after replacing starter when code appeared. Code was not present before starter installation. Could a pinched sensor line running from the junction box under the manifold cause this? What is the best way to test this? Resistance test at sensor pins? Any help greatly appreciated. Code below.

2C9D- DME: Oxygen sensor heater 2 before catalytic converter activation.

Did you ever get this sorted? Was it a bad DME?

[Jackson54]

Originally Posted by Slade_

Did you ever get this sorted? Was it a bad DME?

Yes, o2 wire running on top of valve cover was pinched between the intake manifold. Soldered wires back together, all good for several months now

[Slade_]

Originally Posted by Jackson54

Yes, o2 wire running on top of valve cover was pinched between the intake manifold. Soldered wires back together, all good for several months now

Great news.
Having o2 issues right now.
Hoping my fix will be as straight forward as yours