I had code c1232 and c1255. Reading up it appears c1255 is the 'code of death' so I sourced a second hand ECBM and have just installed. Annoyingly I am still getting the same two codes.


I tried cleaning the grounds before I fitted the new ECBM but did not look at the wheel sensor as I thought code c1255 superseded it.


Has anyone got any ideas of what to look for next, I'm guessing the wheel sensor but could that cause the other code c1255 as an error too. It could be the 2nd hand EBCM is knackered too but I bought through ebay and was assured it was working with no codes.

 

I got codes when my 3rd brake light went out. The tail light harness may have a bad ground as well.

 

If I was planning on having the car for a long time I wouldn't feel bad about having an extra EBCM around. They are not hard to sell either.

 

Thanks for the tips so far. The car is a 2000 Euro spec (I'm in the UK) so the EBCM is the non fixable type but is in the engine bay.


One thing I noticed last night that gave me some hope was when I was driving I could clear the C1255 code and it would not come back on but the C1232 would re appear straight away. When I restarted the car after stopping the C1255 would re appear as well as c1232. I will get the wheel off at the weekend and look at the wiring for the wheel sensor, I read you can swap with the other side to check, is this an easy job?


Thanks again

 

The sensor is in the hub and the hub is hard to remove. You could make jumper wires using alligator clips and wire the left to right and so on. If the code changes to the other side then you know it is the hub. If the problem stays the same then you have a problem with the wiring or perhaps someone sold you another bad EBCM.

The reason the hub is hard to change is because one of the bolts is behind the lower ball joint and the ball joint has to be disconnected to gain access. Why GM did this is beyond my thinking because their truck hubs come off easy.

 

8VETTE7 has provided you some VERY good recommendations and Information. The second I saw the 1255 DTC, I thought of a VOLTAGE ISSUE. That normally results from a LOW VOLTAGE from the ignition switch.

Measure the two test slots on top of all the fuses (especially fuse # 5). Fuse #5 is supplied by the Ignition switch in the ON position. Put the meter on the fuse and have someone turn ON the ignition and watch the voltage. It SHOULD go directly to full battery voltage (as measured at the battery terminals.

If it rises SLOWLY or is much lower than full battery voltage, clean or change the ignition switch (electrical portion of the unit)

You can use a volt meter set on AC Volts (the lowest scale you have on the meter) and measure the output of the WSS. When you rotate the wheel, the AC (pulsed DC) voltage, the voltage level will increase as wheel speed increases.

The Jumper harness female pins are WIDELY KNOWN to fail. They get spread apart and make POOR INTERMITTENT or NO contact with the male pins inside the Wheel Hub Pig Tail Connector.

CHECK AND CORRECT ALL the WSS harness female pins before you waste your time on a new HUB

The sensor which is located inside the blue metal cap on the back of the HUB is just about bullet proof as all that is inside it is a coil of wire around a toothed reluctor that is connected to the wheel shaft.

 

Hi, Thanks again for the tips. Last night I took the wheel sensor wiring connectors apart, they all looked ok but I tried to bend the metal inserts back to try and make a better connection just in case. This made no difference. I then measured the voltage at the connector next to the hub, it read 4.95 volts. When I have read some of the reasons for code C1232 having a voltage of above 4.25 can cause an issue but I am not sure where this should be measured and why the voltage would be exceeding 4.25


I then went on to looking at the battery and fuses. Firstly, the battery was measuring between 12.14 and 12.24 at the terminals. The battery is a red optima type that was new less than 2 years ago. Note, the car doesn't not struggle to start in fact it fires up very easily. I will use a trickle charger to see if I can get more juice into the battery. It could have dropped as I was messing with the car and had doors open, lights on the dash etc.


I then tried to measure the voltage at the fuses but I could not get a reading (on any of the fuses). I just put my multimeter across the two small connectors but I had no reading. This was with the ignition on and then with the car running. I'm not sure what I am doing wrong here, but the electrics must be working otherwise I'd have several error codes.


So, my next plan is to swap over the harnesses from the right wheel to the left and see if that makes a difference, at least it will eliminate a wiring issue from the connector to the hub. I might then swap the battery out and see if that helps at all. I also noticed last night I could no longer clear the C1255 code whilst driving, previously I could do this.


Any further suggestions or pointers to what I am doing wrong in checking the fuses.

 

I then tried to measure the voltage at the fuses but I could not get a reading (on any of the fuses). I just put my multimeter across the two small connectors but I had no reading. This was with the ignition on and then with the car running. I'm not sure what I am doing wrong here, but the electrics must be working otherwise I'd have several error codes.

"I just put my multimeter across the two small connectors but I had no reading. "

If you read across the two test points on the FUSE, unless the fuse is blown, you wil NOT read any voltage.

You need to read each test points to chassis ground. If the fuse is good, both will have voltage.

BC