Fault In Control Module

TA. Diagnostic trouble code (DTC) information

Condition
The control module has a main relay which regulates supply voltage to the motors via four separate motor relays. If the main relay is not activated when a button is pressed in or if the relay is activated with all buttons are in the up position diagnostic trouble code (DTC) PSL/PSR-421 is set.

Possible source
- Defective control module.

Fault symptom(s)
- One or more functions not working.
- Memory buttons do not function
- This diagnostic trouble code (DTC) may occur without any fault symptom being apparent.
- Fault-tracing begins at TB. Fault in control module.









TB. Fault in control module

TB1: Erasing diagnostic trouble code (DTC)
- Ignition OFF.
Erase diagnostic trouble code (DTC).

Move seat using the control buttons.

Read off diagnostic trouble codes (DTCs).

Is the diagnostic trouble code (DTC) set again?

Yes:
- TB3

No:
- TB2





TB2: Fault-tracing information
A diagnostic trouble code (DTC) can be set by a temporary fault occurring in the control module. If the diagnostic trouble code (DTC) is not set again no further action need be taken.

Then continue with:
- Fault corrected

TB3: Replace component
Try a new control module. Control module, Service and Repair

Then continue with:
- Fault corrected