Fault Family System: Powertrain (P-Codes) 4 SAE Codes

Engine Coolant Bypass Valve Position

Diagnostic & Technical Explanation

P23C3 (Engine Coolant Bypass Valve C Position Sensor Circuit) concerns the engine thermal-management bypass valve identified as C — one of the motorized coolant routing valves modern engines use to speed warm-up by holding coolant in the block — and specifically its position feedback sensor or an overheated driver stage in its control module. Scale and mineral deposits stiffening the valve rotor make the motor work harder until the driver flags overcurrent, and the same deposits can shift the position sensor's reported travel out of its learned window.

These 4 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 4 times.

Codes in this family (4)

Code	Definition	Repair coverage
P23C3	Engine Coolant Bypass Valve C Position Sensor Circuit	3 ranked fixes
P23C4	Engine Coolant Bypass Valve C Position Sensor Circuit Low	3 ranked fixes
P23C5	Engine Coolant Bypass Valve C Position Sensor Circuit High	3 ranked fixes
P23C6	Engine Coolant Bypass Valve C Control Circuit Driver Current/Temperature Too High	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)

Need All 15,886 Codes as Data?

Pipe-delimited CSV, Apache Parquet and a relational SQLite database, with commercial application rights and instant download. Built for scan tools, shop software and research - not assembled one web page at a time.

License OEM Complete · $149 Standard (SAE only) · $49

$49 Standard: 9,249 SAE codes · $149 OEM Complete: all 15,886 codes, including 6,637 OEM codes across 32 makes · $149 Heavy Duty: 4,212 fault pairs (J1939) · one-time · compare tiers