ECM not sensing A/C on
05-26-2018, 10:40 PM
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Car: Firebird
Engine: LG4
Transmission: Auto
ECM not sensing A/C on
Another day. another problem. I'm installing a SD TPI unit, AXXB memcal. I only have a handheld scanner. When I turn the A/C on, the primary fan does not come on and the scanner reads A/C Request:OFF. The idle does not seem to speed up either when the A/C is on. Compressor clutch is engaged.
Did some tests and
-Primary fan will turn on when ALDL A and B are jumped.
-Primary fan will turn on when engine reaches approx 228°F
It seems like the ECM is not sensing that the A/C is on. I measured voltage at C2 connector - C9 green wire at the ECM. Is shows approx 12v when the A/C controls are turned on.
Bad ECM?
Did some tests and
-Primary fan will turn on when ALDL A and B are jumped.
-Primary fan will turn on when engine reaches approx 228°F
It seems like the ECM is not sensing that the A/C is on. I measured voltage at C2 connector - C9 green wire at the ECM. Is shows approx 12v when the A/C controls are turned on.
Bad ECM?
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