Aston Martin diagnostic trouble code
P0736: Reverse Gear Incorrect Ratio
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 P0736 means
Reverse Gear Incorrect Ratio
DB9 preliminary diagnostic manual · section 2-176
Manufacturer fault-analysis procedure
Cautions and notes
NOTE: The gear ratio monitoring function and the input
and output speed sensors are internal to the TCM. The
main voltage supply to the TCM is delivered via
C0932-14. The return lines are via ground pins C0932-
13 and 16. Any open circuit fault on the power or
return lines may trigger this group of codes.
and output speed sensors are internal to the TCM. The
main voltage supply to the TCM is delivered via
C0932-14. The return lines are via ground pins C0932-
13 and 16. Any open circuit fault on the power or
return lines may trigger this group of codes.
Test sequence and decision path
1. Check the transmission fluid level. If the fluid
level is low, top-up using the service manual procedure. Check that there are no leaks in the transmission cooling system. Clear the fault code and
run a road test including use of reverse gear.
Check for any logged fault codes.
If P0736 is logged again, go to step 2.
If no gear ratio codes are logged , the cause of the
fault was the low fluid level and the problem is
resolved.
2. Key off. Access the transmission harness and disconnect the transmisison connector.
3. Key on. Check the voltage from harness connector C0932-9 to C0932-13 and 16.
If +12 volts is measured, go to step 3.
If the +12 volt supply is below specification,
check the battery charging and +12 volt circuit
integrity to C0932-14. Service the charging system or wiring as necessary. Reconnect all components and run a brief road test to ensure that the
problem is resolved.
4. Check the condition of the transmission connector socket pin C0932-14.
If the socket is serviceable, the cause of the gear
ratio problem lies within the gearbox.
Replace the gearbox and run a brief road test to
ensure that the problem is resolved.
Open the corresponding manual page for wiring diagrams and figures
level is low, top-up using the service manual procedure. Check that there are no leaks in the transmission cooling system. Clear the fault code and
run a road test including use of reverse gear.
Check for any logged fault codes.
If P0736 is logged again, go to step 2.
If no gear ratio codes are logged , the cause of the
fault was the low fluid level and the problem is
resolved.
2. Key off. Access the transmission harness and disconnect the transmisison connector.
3. Key on. Check the voltage from harness connector C0932-9 to C0932-13 and 16.
If +12 volts is measured, go to step 3.
If the +12 volt supply is below specification,
check the battery charging and +12 volt circuit
integrity to C0932-14. Service the charging system or wiring as necessary. Reconnect all components and run a brief road test to ensure that the
problem is resolved.
4. Check the condition of the transmission connector socket pin C0932-14.
If the socket is serviceable, the cause of the gear
ratio problem lies within the gearbox.
Replace the gearbox and run a brief road test to
ensure that the problem is resolved.