DTC 125

DTC 125 Chart:

A/C Compressor Control Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) has the ability to monitor A/C refrigerant pressure. This is achieved through the use of high side and low side pressure switches. The high side pressure switch is a normally closed switch that is grounded through CKT 251 and monitored by the PCM on CKT 604. When the A/C high pressure line exceeds 430 psi, the switch opens.
To determine the integrity of the A/C high pressure switch the PCM compares the switch status to the A/C high side temperature sensor.

DTC 125 WILL SET WHEN
- DTC 121 not set.
- A/C high pressure switch closed and A/C high side temperature greater than 95°C (203°F).

ACTION TAKEN (PCM WILL DEFAULT TO)
- Disable A/C compressor clutch.
- DTC 124 does not illuminate the Malfunction Indicator Lamp (MIL) (Service Engine Soon).

DTC 125 WILL CLEAR WHEN
The fault no longer exists.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Determines if conditions to set DTC 125 are present.
2. Determines if the A/C high pressure switch is internally shorted.
3. Determines if CKT 604 is shorted to ground, if not shorted the PCM is faulty.

DIAGNOSTIC AIDS
With the engine running, A/C "ON," the A/C high pressure switch status should be "normal" when viewed on the Tech 1. If the switch status is "HI" and no DTC 126 is set, refer to Heating and Air Conditioning.