P1128 LINCOLN Possible Causes
- Crossed HO2S wiring harness connectors
- Powertrain Control Module (PCM) wiring harness connector
How to Fix P1128 LINCOLN Code?
Start by checking the “possible causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light on (or soon-to-be-service engine warning light)
P1128 LINCOLN Meaning
The Diagnostic Trouble Code (DTC) will set whenever the Powertrain Control Module (PCM) detects the upstream oxygen sensor is swapped from Bank to Bank. The Heated Exhaust Gas Oxygen (HEGO) sensor monitor checks and determines if the HO2S signal response to fuel trim change matches the correct engine bank. The code sets when the HO2S being tested is not indicated.