B0452

B0452 00

Blower Fan Circuit, Open







Fault symptom
- Poor cabin heating
- Heater does not start.

On-board diagnosis

Type of diagnosis:
- Continuous

Enable criteria:
- Ignition ON.
- Heater not in rest mode.
- Combustion air fan active

Fault criteria:
- Break in the circuit of the combustion air fan for more than 2.5 s.

System reaction to a fault:
- Heater is switched off.

Checking the wiring harness
- Move the wiring harness at several spots and in several directions to reveal intermittent breaks and short-circuits. Check switches, connectors and crimp connections for oxidation, retracted pins and pin clamping force.

Diagnostic help

Diagnosis regards:
- Electrical fault in connecting leads or component.

Functions in the diagnostic tool related to the fault:

Activate:
- Fan After Cooling
(See also description of readings/activations in diagnostic tool)