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Hello friends, first post so please go easy on me! I'll try to be as concise as possible.
My 07 S60 2.5T FWD has had the drivers-side bulb out for some time and I'm trying to work on it. This has also come with a bulb failure message.
For the life of me I cannot figure out the issue. The bulb turns on momentarily when the vehicle is started, but immediately shuts off. I've done just about everything I can think of besides ruling out the CEM. I pulled it out today to check out connectors and whatnot. I was hoping I could shoot some wires from the CEM as well to see if I'm losing continuity after the CEM.
I wanted to also shoot across the board - if possible. Ultimately my question is this: Is resistance checks from power-in (Fusebox) to power-out (B:7 [driver], B:4 [Passenger]) a valid way of ruling out an issue with the CEM? My results were noted in the attached photo along with all other useful information.
If not, what could I be doing differently? I'm not an expert in electrical but I have gotten myself this far. Any additional comments on my issue would also be helpful. Much love!
I'm actually not sure. I didn't check them before I pulled it out. Please share your train of thought!
On some cars when the CEM detects a fault, codes will be stored and power will be cut off to that circuit. Fixing the fault and erasing the code will restore functionality.
Have seen that several times with for instance a shorted headlamp bulb - new bulb does not work until codes cleared in CEM.
On some cars when the CEM detects a fault codes will be stored and power will be cut off to that circuit. Fixing the fault and erasing the code will restore functionality.
Have seen that several times with for instance a shorted headlamp bulb - new bulb does not work until codes cleared in CEM.
Interesting. I did not know this was possible. It would still be nice if there was a way I could test the CEM while its out. Anyways, I imagine the codes off the CEM cannot be read/cleared by a regular OBDII scanner? Would I need to go to a shop for this.
I imagine the codes off the CEM cannot be read/cleared by a regular OBDII scanner? .
An inexpensive OBD scanner can usually only read emission related codes in the ECM and TCM. (that you would need to read, fix and clear to pass emissions) A compatible scanner can read and clear codes in all the control units. (sample of possible modules below).
An inexpensive OBD scanner can usually only read emission related codes in the ECM and TCM. (that you would need to read, fix and clear to pass emissions) A compatible scanner can read and clear codes in all the control units. (sample of possible modules below).
So, I was able to run a scan of the CEM. I am getting a 8A20 "Low beam Left, Signal too low" fault. I was able to clear it real time and watch the light come back on momentarily, then back off. I think I need to re-check the grounds AGAIN?
CEM Diagnosis. Electrical prowess needed!
