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

Reductant Valve Circuit Performance

Diagnostic & Technical Explanation

P202F (Reductant/Regeneration Supply Control Circuit Range/Performance) covers the solenoid valves that purge residual reductant from the dosing line after injection or regulate the compressed-air assist supply, protecting the system from urea crystallizing inside the lines when the vehicle shuts off. A valve that will not open leaves DEF standing in the line to crystallize on the next cold soak, while a valve stuck open bleeds system air pressure; both conditions and the underlying circuit-open/short fault share the same electrical diagnosis and valve-replacement repair.

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
P202F	Reductant/Regeneration Supply Control Circuit Range/Performance	3 ranked fixes
P2062	Reductant/Regeneration Supply Control Circuit/Open	3 ranked fixes
P2063	Reductant/Regeneration Supply Control Circuit Low	3 ranked fixes
P2064	Reductant/Regeneration Supply Control Circuit High	3 ranked fixes
P20A0	Reductant Purge Control Valve A Circuit /Open	3 ranked fixes
P20A1	Reductant Purge Control Valve A Performance	3 ranked fixes
P20A2	Reductant Purge Control Valve A Circuit Low	3 ranked fixes
P20A3	Reductant Purge Control Valve A Circuit High	3 ranked fixes
P20A4	Reductant Purge Control Valve A Stuck Open	3 ranked fixes
P20A5	Reductant Purge Control Valve A Stuck Closed	3 ranked fixes
P20A6	Reductant Injection Air Pressure Control Valve Circuit/Open	3 ranked fixes
P20A7	Reductant Injection Air Pressure Control Valve Performance	3 ranked fixes
P20A8	Reductant Injection Air Pressure Control Valve Circuit Low	3 ranked fixes
P20A9	Reductant Injection Air Pressure Control Valve Circuit High	3 ranked fixes
P20AA	Reductant Injection Air Pressure Control Valve Stuck Open	3 ranked fixes
P20AB	Reductant Injection Air Pressure Control Valve Stuck Closed	3 ranked fixes
P24DB	Reductant Purge Control Valve B Circuit /Open	3 ranked fixes
P24DC	Reductant Purge Control Valve B Performance	3 ranked fixes
P24DD	Reductant Purge Control Valve B Circuit Low	3 ranked fixes
P24DE	Reductant Purge Control Valve B Circuit High	3 ranked fixes
P24DF	Reductant Purge Control Valve B Stuck Open	3 ranked fixes
P24E0	Reductant Purge Control Valve B Stuck Closed	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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