P1657

Read the instructions below then start the fault diagnostic procedure.

Symptom: A/C not working.

P1657

Fault symptoms

•	A/C 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. A/C request has previously arrived on the bus on some occasion (cars with A/C). Output active.

Fault criteria:

-	Output voltage exceeding 2V 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: (See section Fault handling III, other emission-related components and functions 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 A/C relay.

See also the description of activations under Menu "Activation" 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.