Body
Generic/SAE
OBD-II Fault Code
B2451: Aux Heater Fuel Pump Circuit Short to Ground
Meaning, symptoms, likely causes, diagnostic checks and repair guidance for B2451.
Fuel system
Use this category to narrow your checks before replacing parts.
High
Severity is a general guide. Confirm with scan-tool data and vehicle symptoms.
What B2451 usually means
Aux Heater Fuel Pump Circuit Short to Ground.
Common symptoms
Body/accessory warning lamp or feature not working; Hard start, hesitation, stalling or inaccurate fuel reading depending on component
Likely causes
Low fuel pressure; Faulty pump/regulator/sensor; Wiring fault; Clogged filter; Injector fault; Wire shorted to chassis/ground; Internal component short
Diagnostic checks
Check related fuses, connectors, grounds and switch/module power supply; Check fuel pressure and sensor data; Inspect pump/injector fuses, relay, wiring and grounds; Inspect harness for rubbing/pinch points and check resistance to ground
Repair guidance
Repair wiring/relay issues, replace clogged filter, failed pump/sensor/injector only after testing; Repair insulation/harness damage or replace internally shorted component
Verification after repair
Operate the affected body/accessory system and rescan