C1978 Engine Code Repair

Meaning of C1978 engine trouble code is a kind of chassis trouble code and C1978 if your catalytic convertor fails completely, you eventually won't be able to keep the car running. Your gas mileage will also be terrible, so you should try and fix it as soon as you can. Unfortunately, the average replacement cost is around $2,140 and you can't do it yourself unless you're an experienced mechanic.

C1978 Fault Symptoms :

C1978 Possible Solution:

Air Conditioning Pressure Sensor (ACP) Insufficient Pressure Change Each time the A/C clutch engages, the PCM is looking for a pressure change in the refrigerant. If the change in pressure is outside of the calibration the DTC will set. A/C system mechanical failure Open ACP or VREF circuit A/C sensor damaged A/C system electrical failure A/C clutch always engaged Verify A/C system function, including refrigerant charge.

C1978 Code Meaning :

Is the fuel pump sometimes not priming when you turn the key to ON(II)? Start by measuring the fuel pressure and checking whether you have bright white-bluish spark at all four plugs. The mechanical timing is also something that you should check, as we mentioned above.

C1978 DTC reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.