Fault Family System: Powertrain (P-Codes) 10 SAE Codes

O2 Sensor Signal Correlation

Diagnostic & Technical Explanation

Code P0040 (O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1) sets when the ECM compares two oxygen sensor signals and finds they correlate as if the connectors were swapped, or the signals otherwise disagree with their expected bank/position relationship. This is most often a technician wiring mix-up after prior service, a chafed harness section shorting two sensor signal wires together, or a failing sensor.

These 10 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 10 times.

Codes in this family (10)

Code	Definition	Repair coverage
P0040	O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 2 Sensor 1	3 ranked fixes
P0041	O2 Sensor Signals Swapped Bank 1 Sensor 2/Bank 2 Sensor 2	3 ranked fixes
P00D5	HO2S Sensor Correlation Bank 1 Sensor 1/Bank 1 Sensor 2	3 ranked fixes
P00D6	HO2S Sensor Correlation Bank 2 Sensor 1/Bank 2 Sensor 2	3 ranked fixes
P2278	O2 Sensor Signals Swapped Bank 1 Sensor 3/Bank 2 Sensor 3	3 ranked fixes
P2416	O2 Sensor Signals Swapped Bank 1 Sensor 2/Bank 1 Sensor 3	3 ranked fixes
P2417	O2 Sensor Signals Swapped Bank 2 Sensor 2/Bank 2 Sensor 3	3 ranked fixes
P241A	O2 Sensor Signals Swapped Bank 1 Sensor 1/Bank 1 Sensor 2	3 ranked fixes
P241B	O2 Sensor Signals Swapped Bank 2 Sensor 1/Bank 2 Sensor 2	3 ranked fixes
P2CA4	Particulate Filter Pressure Sensor Signals Swapped A/B	3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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