Aston Martin diagnostic trouble code

P1127: Exhaust Temperature Out of Range, O2 Sensor Tests Not Completed

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
Oxygen sensors
Manual coverage
V8 Vantage, DB9
Warning-lamp status
V8 Vantage: Not stated; DB9: MIL

What Aston Martin code P1127 means

Exhaust Temperature Out of Range, O2 Sensor Tests Not Completed

DB9 preliminary diagnostic manual · section 2-214

Manufacturer fault-analysis procedure

Manual fault definition

P1127 - Exhaust not warm enough, downstream
oxygen sensors not tested.

Cautions and notes

NOTE: During engine warm-up at idle speed with the
vehicle stationary, the rear oxygen sensors may not
reach operating temperature. If this is suspected, run
the vehicle on the road through a vigorous series of
acceleration cycles to fully warm up the exhaust and
then repeat the KOER test sequence.

CAUTION: This code may be generated in the
Primary or Secondary Powertrain Control Module
(PCM). Check that you are working on the correct
half of the engine.

Test sequence and decision path

1. Connect the WDS or scan tool. Key on.

2. Run the engine and monitor the oxygen sensor
heaters. The heaters will be commanded to come
on and remain on when the engine is warm.
When the engine is fully warmed up and all
HO2S heaters are commanded on, run the KOER
test to ensure that there is not a problem.
If the HO2S heaters are commanded on and erroneous oxygen readings occur, analyse the problem using the P code procedure for the suspect
sensor.
Open the corresponding manual page for wiring diagrams and figures