Aston Martin diagnostic trouble code

P0641: Transmission Sensor Supply Voltage too High or too Low

Use this reference to understand the recorded condition, confirm the available V8 Vantage or DB9 manual coverage, and follow the documented diagnostic checks before replacing parts.

Code family
Powertrain
Vehicle system
Transmission
Manual coverage
DB9
Warning-lamp status
DB9: MIL

What Aston Martin code P0641 means

Transmission Sensor Supply Voltage too High or too Low

DB9 preliminary diagnostic manual · section 2-154

Manufacturer fault-analysis procedure

Cautions and notes

NOTE: This sensor supply is internal to the TCM. If the
12 volt VBATT signal is within specification and P0641
is logged, the TCM is faulty.

Test sequence and decision path

1. Connect the WDS or scan tool. Check that P0641
is logged.

2. Key off. Disconnect the transmission harness at
the gearbox.

3. With the ignition switched off, check for +12 vots
from transmission harness connector pin C 0932-
14 (VBatt) to pin C0932-13 and 16 (Ground).
If +12 volts is available, go to step 4.
If +12 volts is not available, service the +12 volt
or ground circuit as necessary. Clear the fault
code and run a KOER test to ensure that the problem is resolved.

4. Check the condition of the pins and sockets in
both halves of C0932.
If any fault is identified, service the connector as
necessary. Clear the P0641 code and run a KOER
test to ensure that the problem is resolved.
If no fault is identified, replace the mechatronic
unit. Clear the P0641 code and run a KOER test
to ensure that the problem is resolved.
Open the corresponding manual page for wiring diagrams and figures