AHM/PHM / B0448 01

Read the instructions below then start the fault diagnostic procedure.

Symptom: Poor cabin heating Heater does not start.

B0448 01

Fault symptom

Poor cabin heating

Heater does not start.

On-board diagnosis

Type of diagnosis:

Continuous

Enable criteria:

Ignition ON.

Combustion air fan not active

Heater not in rest mode.

Fault criteria:

Combustion air fan shorted to B+ for more than 1.3 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)