Fault Family System: Powertrain (P-Codes) 22 SAE Codes

EGR Temp Sensor Circuit

Diagnostic & Technical Explanation

Code P040A (EGR Temperature Sensor A Circuit) sets when the ECM sees an open, shorted, or implausible resistance from an EGR temperature sensor (positions A through D on multi-cooler/multi-loop platforms), or finds a correlation mismatch between two EGR temperature sensors that should track together. Causes are a corroded connector exposed to exhaust heat-cycling, a failed thermistor element, or chafed wiring near the EGR cooler/tube.

These 22 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 22 times.

Codes in this family (22)

Code	Definition	Repair coverage
P040A	EGR Temperature Sensor A Circuit	4 ranked fixes
P040B	EGR Temperature Sensor A Circuit Range/Performance	4 ranked fixes
P040C	EGR Temperature Sensor A Circuit Low	4 ranked fixes
P040D	EGR Temperature Sensor A Circuit High	4 ranked fixes
P040E	EGR Temperature Sensor A Circuit Intermittent/Erratic	4 ranked fixes
P040F	EGR Temperature Sensor A/B Correlation	4 ranked fixes
P041A	EGR Temperature Sensor B Circuit	4 ranked fixes
P041B	EGR Temperature Sensor B Circuit Range/Performance	4 ranked fixes
P041C	EGR Temperature Sensor B Circuit Low	4 ranked fixes
P041D	EGR Temperature Sensor B Circuit High	4 ranked fixes
P041E	EGR Temperature Sensor B Circuit Intermittent/Erratic	4 ranked fixes
P04CE	EGR Temperature Sensor C Circuit	4 ranked fixes
P04CF	EGR Temperature Sensor C Circuit Range/Performance	4 ranked fixes
P04D0	EGR Temperature Sensor C Circuit Low	4 ranked fixes
P04D1	EGR Temperature Sensor C Circuit High	4 ranked fixes
P04D2	EGR Temperature Sensor C Circuit Intermittent/Erratic	4 ranked fixes
P04E5	EGR Temperature Sensor D Circuit	4 ranked fixes
P04E6	EGR Temperature Sensor D Circuit Range/Performance	4 ranked fixes
P04E7	EGR Temperature Sensor D Circuit Low	4 ranked fixes
P04E8	EGR Temperature Sensor D Circuit High	4 ranked fixes
P04E9	EGR Temperature Sensor D Circuit Intermittent/Erratic	4 ranked fixes
P24F2	EGR Temperature/Charge Air Cooler Temperature Correlation	4 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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