P1622

DIAGNOSTIC TROUBLE CODES P1621, P1622
A/C relay, output from control module low/high
No continuity or shorting to ground/batt+

Fault Symptom.
No A/C function

Condition
No continuity or shorting to ground/batt+ in the circuit to pin 33

Diagnostic Procedure.
1. Activate the "AC RELAY" function in the "ACTIVATE" menu and listen to check whether the A/C relay is working.

If the relay works as it should, continue at "Before Replacing Control Module" for further diagnostic instructions. Before Replacing A Control Module
If the relay does NOT work, continue as described below.

2. With the ignition switched OFF, connect a BOB between the control module and it's cable.

With the ignition switch in the DRIVE position and the A/C function activated, check whether current is present on pin 40 of the MOTRONIC control module.

If it is, proceed to step 2.
If it is NOT, check the A/C function.

3. Start the engine and check whether the control module grounds pin 25 when current is present on pin 40 (delay in the control module for idling compensation).

If the control module grounds pin 25, check the A/C function.
If the control module does NOT ground pin 25, continue at "Before Replacing Control Module" for further diagnostic instructions. Before Replacing A Control Module