Reviewed Ford-related codes

DTC lookup

This library stays small on purpose. P1000 remains the site’s center; related codes are included only when they help interpret incomplete readiness.

P1000

Usually low by itself

OBD System Readiness Test Not Complete

Manufacturer-specific Ford status indicating that required OBD-II readiness / self-tests have not completed.

P0420

Moderate — diagnose the related fault

Catalyst System Efficiency Below Threshold (Bank 1)

The PCM has determined catalyst efficiency is below the OBD threshold for bank 1 — a different finding from P1000 readiness status.

P0455

Moderate — diagnose the related fault

EVAP System Gross Leak Detected

The evaporative emissions system reported a gross leak condition — separate from P1000 incomplete-readiness status.

P0171

Moderate — diagnose the related fault

System Too Lean (Bank 1)

Bank 1 fuel control is reporting a lean condition — a fuel-system DTC, not a readiness-status code.

P0135

Moderate — diagnose the related fault

O2 Sensor Heater Circuit (Bank 1, Sensor 1)

Heater circuit fault for bank 1 sensor 1 — distinct from P1000 incomplete readiness.

P0401

Moderate — diagnose the related fault

EGR Insufficient Flow

Detected EGR flow is below the expected threshold — an EGR diagnosis, not a readiness-status code.

C116A

Moderate — diagnose the related fault

ABS Pressure Transducer / Brake Switch Mismatch

Manufacturer-specific chassis/ABS status: the stoplamp/brake-switch message does not agree with hydraulic brake-pressure input during that ignition cycle.