A/C Compressor Control - Above Upper Limit

P1456

A/C Compressor Control - Above Upper Limit

Function
The magnetic clutch of the A/C compressor is supplied with battery voltage via a relay.
The coil of the relay is supplied with battery voltage via the DME relay on one side and with ground via the DME control module on the other side. Only the wire from DME control module, pin 62, to the A/C relay, terminal 85, is monitored during diagnosis.

Diagnosis conditions
A fault is detected and stored in the memory when the engine speed is over 80 rpm and the battery voltage lies between 7.5 and 17 V.

P1455-P1457:

Wiring Diagram







Diagnosis Procedure

DTC P1455







DTC P1456







DTC P1457







1 Check control wire for A/C relay, pin 2, for open circuit.

1. Remove A/C relay.
2. Connect special tool 9616 to wiring harness (DME control module connector).
3. Connect ohmmeter to special tool 9616, pin 62, and A/C relay, pin 2.
Display: 0 - 5 ohms

2 Check control wire for A/C relay, pin 2, for short circuit to B+.

1. Remove A/C relay.
2. Remove DME control module connector.
3. Connect voltmeter (positive) to A/C relay, pin 2, and ground.
Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

3 Check control wire for A/C relay, pin 2 (terminal 85), for short circuit to ground.

1. Remove A/C relay.
2. Remove DME control module connector.
3. Connect ohmmeter to ground and pin 2 (terminal 85).
Display: Infinity ohm

If 0 - 5 ohms is displayed, check wiring harness for chafing and pinching damage.