P1641

Symptom: Car fails to start.

P1641

Fault symptom

Car fails to start.

Conditions

Diagnostic trouble code (DTC) stored in the engine management system if alarm code absent.

Diagnostic procedure

1 Check the engine management system diagnostic trouble code (DTC)

-	Connect the ISAT scan tool.

-	Select "TRIONIC", "MOTRONIC 2.8.1" or "MOTRONIC 2.10", depending on the engine management system in question.

-	Select "READ FAULT CODES".

Has DTC P1641 been stored?

yes

Continue with point 2.

no

Continue fault diagnosis on the engine management system as described in Service Manual 2:7.

2 Program the VSS alarm code

-	Select "THEFT ALARM".

-	Select "IMMOBILIZING".

-	Program the correct alarm code in the VSS electronic control module.

-	Select "TRIONIC", "MOTRONIC 2.8.1" or "MOTRONIC 2.10", depending on the engine management system in question.

-	Select "CLEAR FAULT CODES".

-	Try to start the car.

Will the car start?

yes

The steps taken to rectify the fault were correct.

no

The alarm code is incorrect or absent. Continue fault diagnosis on the engine management system as described in Service Manual 2:7.

3 Check the alarm code status in VSS

-	Select "THEFT ALARM".

-	Select "READ VALUES".

-	Select "ALARM CODE".

Is the alarm code correct?

yes

Continue with point 4.

no

The alarm code is incorrect or absent. Continue fault diagnosis on the engine management system as described in Service Manual 2:7.

4 Final check

Start the car and check to see if the fault symptom remains.

Is the problem still present?

yes

See "Before replacing a control module".

no

The remedial measures taken were correct or the fault is of intermittent nature.