Reset of OBD1 AC code
Thread Starter
Newbie
Joined: May 2015
Posts: 7
Likes: 0
Mercedes 300E 1990
Reset of OBD1 AC code
Dear forum,
I am trying to reset my 8-pin OBD1 AC code (pin 7) on my 300E, M103, 1990.
It holds one error code (30) which refers to a Coolant Pump short-circuit. I assume they mean the aux. pump.
The aux. pump was defect some years ago and was replaced, so the code may very well have lingered on since then.
Anyway, I am trying to reset the code, in order to have a clean baseline, in an attempt to solve an intermittent AC issue.
I have tried to reset it with the analogue pulse reader (the one with three wires), by pressing the reset button for 8-10 seconds after reading the code, but the code remains.
I also noticed than when reading the code, the Air Recycle button on the dash starts flashing.
I have reset the ASD code many times by jumping pin 1 and 5, which I assume is what the reset button does - but for pin 7, it doesn't work.
Has anyone here had success clearing AC codes?
BR
Viggo
I am trying to reset my 8-pin OBD1 AC code (pin 7) on my 300E, M103, 1990.
It holds one error code (30) which refers to a Coolant Pump short-circuit. I assume they mean the aux. pump.
The aux. pump was defect some years ago and was replaced, so the code may very well have lingered on since then.
Anyway, I am trying to reset the code, in order to have a clean baseline, in an attempt to solve an intermittent AC issue.
I have tried to reset it with the analogue pulse reader (the one with three wires), by pressing the reset button for 8-10 seconds after reading the code, but the code remains.
I also noticed than when reading the code, the Air Recycle button on the dash starts flashing.
I have reset the ASD code many times by jumping pin 1 and 5, which I assume is what the reset button does - but for pin 7, it doesn't work.
Has anyone here had success clearing AC codes?
BR
Viggo
Thread Starter
Newbie
Joined: May 2015
Posts: 7
Likes: 0
Mercedes 300E 1990
As I said. I have reset the ASD code many times.
Yes, it comes back after a while because the underlying fault has not been corrected yet - but it can be cleared as long as the ASD relay hasn't yet detected the fault again, which usually requires some driving.
In the case of the AC and this continuity fault, the short is detected immediately, which I guess is why I don't get a window of clearance.
I unplugged the pump today with great difficulty, as the terminals were quite corroded, virtually creating an open loop situation, but even after sanding down the terminals, I had far too much resistance - so the pump is clearly shot. It also does not start when 12 V is applied.
Still strange though that the code says 'Pump Short Cicuit, since it is really the opposite that is the case.
But maybe the Klima relay detects both.
/Viggo
Yes, it comes back after a while because the underlying fault has not been corrected yet - but it can be cleared as long as the ASD relay hasn't yet detected the fault again, which usually requires some driving.
In the case of the AC and this continuity fault, the short is detected immediately, which I guess is why I don't get a window of clearance.
I unplugged the pump today with great difficulty, as the terminals were quite corroded, virtually creating an open loop situation, but even after sanding down the terminals, I had far too much resistance - so the pump is clearly shot. It also does not start when 12 V is applied.
Still strange though that the code says 'Pump Short Cicuit, since it is really the opposite that is the case.
But maybe the Klima relay detects both.
/Viggo
