Corroded, loose or damaged battery and ground connections that raise circuit voltage; Faulty engine control module power relay or fuse box connection feeding the injector group; Chafed or shorted injector supply wiring contacting a higher-voltage source; Failed engine control module driver or internal voltage regulation for that injector group; Poor engine ground strap or chassis ground causing voltage reference errors; Aftermarket electrical accessories or a faulty alternator pushing charging voltage too high; Damaged injector connector or harness pigtail allowing voltage to backfeed

DTC codes / P21xx · Fuel and air metering / P2148

P2148Fuel Injector Group 'A' Supply Voltage Circuit High

Q: What does code P2148 mean?

Fuel Injector Group 'A' Supply Voltage Circuit High. P2148 means the engine control module has detected an abnormally high voltage on the power supply circuit that feeds a group of fuel injectors, usually the bank that shares a common power feed. The module expects the supply voltage to stay within a normal range, and a high reading tells it that the circuit is seeing excessive voltage or an open return path rather than the controlled voltage it commands.

P2148 means the engine control module has detected an abnormally high voltage on the power supply circuit that feeds a group of fuel injectors, usually the bank that shares a common power feed. The module expects the supply voltage to stay within a normal range, and a high reading tells it that the circuit is seeing excessive voltage or an open return path rather than the controlled voltage it commands.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough running or misfire if the high voltage has damaged or disabled injector operation
Engine may crank but fail to start when the injector group loses its proper supply
Reduced power or limp-home mode triggered by the engine control module
Intermittent stumble or hesitation that comes and goes with vibration or temperature
Often no symptoms besides the warning light when the fault is a brief voltage spike

Common causes, most likely first

Corroded, loose or damaged battery and ground connections that raise circuit voltage
Faulty engine control module power relay or fuse box connection feeding the injector group
Chafed or shorted injector supply wiring contacting a higher-voltage source
Failed engine control module driver or internal voltage regulation for that injector group
Poor engine ground strap or chassis ground causing voltage reference errors
Aftermarket electrical accessories or a faulty alternator pushing charging voltage too high
Damaged injector connector or harness pigtail allowing voltage to backfeed

How to diagnose and fix it

Read all stored and pending codes and record freeze-frame data before clearing anything
Inspect and test the battery, charging system and main grounds for excessive voltage or resistance
Check the injector group power relay, fuses and fuse box terminals for corrosion or looseness
Disconnect the injector group harness and measure supply voltage with the key on to confirm the high reading
Inspect the injector supply wiring for chafing, shorts to voltage and damaged connectors
Test the engine control module ground and reference circuits before condemning the module
If wiring and grounds are sound, perform a module driver test or substitute a known-good module to confirm internal failure

High voltage often starts at the ground

A high voltage reading on an injector supply circuit is frequently caused by a bad ground rather than a short to power, because a lifted ground raises the reference voltage the module sees.
Technicians who replace the engine control module first often miss a corroded ground strap or battery terminal that is the real source of the elevated voltage.
This code does not always mean the injectors themselves are faulty, and replacing injectors without testing the supply circuit wastes money and does not clear the fault.
A failing alternator or voltage regulator that pushes charging voltage above normal can set this code on vehicles with sensitive injector supply monitoring.
The same high-voltage condition can damage the engine control module driver over time, so a fault that returns after repair should prompt a repeat voltage-drop test on every ground in the injector group circuit.

Can I keep driving with P2148?

You can usually drive a short distance to a repair shop if the engine runs normally, but avoid hard acceleration and long trips because excessive voltage can damage injectors or the engine control module. If the engine misfires, stalls or enters limp mode, stop driving and have the vehicle towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.