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

HV Interlock Service Disconnect

Diagnostic & Technical Explanation

Code P0A0A sets when the HV interlock / service-disconnect loop — a low-voltage sense wire daisy-chained through every HV connector cover, service plug, and junction-box lid on the vehicle — does not read a continuous closed circuit, so the system inhibits high-voltage operation as a safety measure. The most common physical causes are a connector cover or the manual service plug that vibrated loose without being fully reseated, a pinched or broken interlock wire at one segment of the chain, and a failed interlock-sense pin inside one connector. Because the loop spans the whole vehicle's HV hardware, isolating which segment is open requires working through the chain systematically rather than assuming the fault is at any one connector.

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
P0A0A	High Voltage System Interlock Circuit A	3 ranked fixes
P0A0B	High Voltage System Interlock Circuit A Performance	3 ranked fixes
P0A0C	High Voltage System Interlock Circuit A Low	3 ranked fixes
P0A0D	High Voltage System Interlock Circuit A High	3 ranked fixes
P0A0E	High Voltage System Interlock Circuit A Intermittent	3 ranked fixes
P0B33	High Voltage Service Disconnect Circuit	3 ranked fixes
P0B34	High Voltage Service Disconnect Circuit Performance	3 ranked fixes
P0B35	High Voltage Service Disconnect Circuit Low	3 ranked fixes
P0B36	High Voltage Service Disconnect Circuit High	3 ranked fixes
P0B37	High Voltage Service Disconnect Open	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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