Fault Conditions

P1656

A/C Relay Coil Circuit. Open/short to Ground.







Fault symptoms
- A/C malfunctioning.
- Compressor may run continuously.

On-Board Diagnostics

Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
- Ignition in ON position. A/C request has previously arrived on bus on some occasion (cars with A/C). Output not active.

Fault criteria:
- Output voltage below 2 V for more than 1 s.

Dependents:
- None.

System reaction to a fault:
- Air mass control A/C compensation blocked.

OK report:
- Enable criteria fulfilled. A/C (Bus from DICE) is ON and fault criteria not fulfilled within 1.5 s.

Fault handling: (For more information, Fault Handling III Other Emission-Related Components & Function)

- Type III. CHECK ENGINE does not go on.

Diagnostic help
Fault diagnosis concerns electrical fault in connecting leads or in the relay.

Functions in the diagnostic tool related to the fault:
- Activate A/C relay output.

For more information, Scan Tool Testing and Procedures

Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.

Proceed to Diagnostic Procedures Checking the Relay Power Supply