Fault Conditions

P1657
A/C Relay Coil Circuit. Short to B+.

Fault symptoms
- AC not working.

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. AC request has previously arrived on the bus on some occasion (cars with AC). Output active.

Fault criteria:
- Output voltage exceeding 2V for more than 1 S.

Dependents:
- None.

System reaction to a fault:
- Air mass control AC compensation blocked.

OK report:
- Enable criteria fulfilled. AC (Bus from DICE) is ON and fault criteria not fulfilled within 1.5 S.

Fault handling: See "Fault diagnosis, general" for more information.
- Type III. CHECK ENGINE does not go on.

Diagnostic help
Fault diagnosis concerns electrical faults in connecting cables or in the relay.

Diagnostic tool functions related to this fault are:
- Activation of output for AC relay.

See also the description of activating functions under "Fault diagnosis, general" for more information.

Check the wiring
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic tool while doing this.

Proceed to Diagnostic Procedures Checking the Relay Power Supply