Aston Martin diagnostic trouble code
P1633: Fault flag Indicating a Low/Lack Of Keep Alive Memory Voltage
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
- Electrical and control modules
- Manual coverage
- V8 Vantage, DB9
- Warning-lamp status
- V8 Vantage: MIL; DB9: MIL
What Aston Martin code P1633 means
Fault flag Indicating a Low/Lack Of Keep Alive Memory Voltage
DB9 preliminary diagnostic manual · section 2-252
Manufacturer fault-analysis procedure
Manual fault definition
P1633 - Low or missing KAPWR voltage. This is a
MIL code.
MIL code.
Test sequence and decision path
1. Connect the WDS and record all logged DTCs.
Ensure that P1633 is logged. Ensure that the Battery Disconnect Switch is ON.
2. Check the battery voltage. If battery voltage is less
than 12.5 - 13.0 volts, service the battery as
instructed in the battery care manual. Clear the
P1633 code and run a KOER test to ensure that
the problem is resolved.
If the P1633 is logged again, go to step 3.
3. Check the condition of the following fuses:
In-Line Fuse 60A
Underbonnet fuse F12 KAPWR to primary PCM
Underbonnet fuse F1 KAPWR to secondary PCM
If the fuses are good, go to step 4
If any fuse is blown, service the KAPWR circuit as
necessary. Clear the P1633 code and run a KOER
test to ensure that the problem is resolved.
4. Check the voltage from underbonnet fuses F12
and F1 to chassis ground.
If full battery voltage is measured. at the fuses, go
to step 5.
If less than battery voltage is measured at the
fuses, service the battery to fusebox circuit as
necessary. Clear the P1633 code and run a KOER
test to ensure that the problem is resolved.
5. Connect the break-out box to the suspect PCM.
Measure the voltage from primary PCM C0635-
45 to chassis ground and from secondary PCM
CC0638-45 to chassis ground.
If full battery voltage is measured. at both PCMs,
go to step 6.
If less than battery voltage is measured at either
PCM, service the circuit as necessary. Clear the
P1633 code and run a KOER test to ensure that
the problem is resolved.
6. Analyse this fault as an intermittent fault in the
KAPWR circuit.
Open the corresponding manual page for wiring diagrams and figures
Ensure that P1633 is logged. Ensure that the Battery Disconnect Switch is ON.
2. Check the battery voltage. If battery voltage is less
than 12.5 - 13.0 volts, service the battery as
instructed in the battery care manual. Clear the
P1633 code and run a KOER test to ensure that
the problem is resolved.
If the P1633 is logged again, go to step 3.
3. Check the condition of the following fuses:
In-Line Fuse 60A
Underbonnet fuse F12 KAPWR to primary PCM
Underbonnet fuse F1 KAPWR to secondary PCM
If the fuses are good, go to step 4
If any fuse is blown, service the KAPWR circuit as
necessary. Clear the P1633 code and run a KOER
test to ensure that the problem is resolved.
4. Check the voltage from underbonnet fuses F12
and F1 to chassis ground.
If full battery voltage is measured. at the fuses, go
to step 5.
If less than battery voltage is measured at the
fuses, service the battery to fusebox circuit as
necessary. Clear the P1633 code and run a KOER
test to ensure that the problem is resolved.
5. Connect the break-out box to the suspect PCM.
Measure the voltage from primary PCM C0635-
45 to chassis ground and from secondary PCM
CC0638-45 to chassis ground.
If full battery voltage is measured. at both PCMs,
go to step 6.
If less than battery voltage is measured at either
PCM, service the circuit as necessary. Clear the
P1633 code and run a KOER test to ensure that
the problem is resolved.
6. Analyse this fault as an intermittent fault in the
KAPWR circuit.