DTC P1127: Cold Exhaust: Condition
WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when Powertrain Control Module (PCM) does not detect enough exhaust temperature to test rear heated oxygen sensor (HO2S). Possible causes are:
- Engine is not warm enough to perform KOER self-test.
- Exhaust system is too cold.