The PCM(Engine Control Module) receives pressure signal in the A/C refrigerant high pressure side from the A/C refrigerant pressure sensor. This input indicates how much load the A/C compressor is putting on the engine and is one of the factors used by the PCM in order to determine the idle air control position for the idle speed. The circuits consist of a 5V reference and a ground, both provided by the PCM, and a signal from the sensor. The signal is a voltage which is proportional to the A/C pressure from 0 to 5V. Low pressure produces a low voltage signal and high pressure a high-voltage signal.
PCM sets DTC P0553 if the PCM detects signal higher than the possible range of a properly operating sensor.
Item
Detecting Condition
Possible Cause
DTC Strategy
Electrical Check
Short to power in signal circuit
Open in ground circuit
Poor connection or damaged harness
Faulty A/C pressure sensor
Enable Conditions
10V < Battery voltage < 16V
Threshold value
Signal voltage > 4.7V
Diagnosis Time
30 sec.
MIL On Condition
-