Fault Family System: Powertrain (P-Codes) 6 SAE Codes

AFCM Power Relay Circuit

Diagnostic & Technical Explanation

Code P2A32 (AFCM Power Relay Control Circuit/Open) sets when the alternative fuel control module cannot verify its own main power relay - the control or sense leg reads open, shorted, or out of range when the ECM commands the relay on. Because the AFCM has to be powered before it can manage CNG/LPG tank valves and vaporizer heaters, a relay fault here typically defaults the vehicle to gasoline-only operation. Common causes are a welded or open relay contact, a corroded relay socket, or chafed wiring between the relay and the AFCM.

These 6 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 6 times.

Codes in this family (6)

Code	Definition	Repair coverage
P2A32	AFCM Power Relay Control Circuit/Open	4 ranked fixes
P2A33	AFCM Power Relay Control Circuit Low	4 ranked fixes
P2A34	AFCM Power Relay Control Circuit High	4 ranked fixes
P2A35	AFCM Power Relay Sense Circuit	4 ranked fixes
P2A36	AFCM Power Relay Sense Circuit Low	4 ranked fixes
P2A37	AFCM Power Relay Sense Circuit High	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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