A sensor on the reference voltage G circuit internally shorted to ground; Chafed or damaged wiring in the reference voltage circuit contacting ground; Corroded or loose connector pins at a sensor or the PCM; Moisture intrusion into a sensor connector causing a partial short; A faulty PCM driver for the reference voltage output (rare)

DTC codes / P26xx · Computer and output circuits / P262D

P262DSensor Reference Voltage G Circuit Low

Q: What does code P262D mean?

Sensor Reference Voltage G Circuit Low. P262D indicates that the powertrain control module (PCM) has detected a low voltage condition on the sensor reference voltage circuit labeled 'G', which is a dedicated 5-volt supply used by one or more sensors. The PCM monitors this circuit and sets the code when the voltage falls below a calibrated threshold, typically because the circuit is shorted to ground or a connected sensor is drawing excessive current.

P262D indicates that the powertrain control module (PCM) has detected a low voltage condition on the sensor reference voltage circuit labeled 'G', which is a dedicated 5-volt supply used by one or more sensors. The PCM monitors this circuit and sets the code when the voltage falls below a calibrated threshold, typically because the circuit is shorted to ground or a connected sensor is drawing excessive current.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough running or misfire if the affected sensors include the mass airflow or throttle position sensor
Reduced engine power or limp mode if the reference voltage feeds critical sensors
Poor fuel economy or erratic shifting if transmission sensors share the circuit
Intermittent stalling or hesitation when the low voltage condition is sporadic

Common causes, most likely first

A sensor on the reference voltage G circuit internally shorted to ground
Chafed or damaged wiring in the reference voltage circuit contacting ground
Corroded or loose connector pins at a sensor or the PCM
Moisture intrusion into a sensor connector causing a partial short
A faulty PCM driver for the reference voltage output (rare)

How to diagnose and fix it

Scan all modules and record freeze-frame data to identify which sensors share the reference voltage G circuit
Visually inspect the harness and connectors for chafing, corrosion, or moisture, especially near the sensors on that circuit
Disconnect sensors one at a time on the G circuit and observe whether the reference voltage returns to normal, isolating the faulty component
Measure resistance from the reference voltage wire to ground with the PCM disconnected to check for a short
Repair any damaged wiring or replace corroded terminals and clear the code
If no sensor or wiring fault is found, test the PCM reference voltage output with a known-good load and replace the PCM only if it fails

Reference Voltage G Circuit Pitfalls

Many technicians replace the sensor that appears faulty without checking the shared reference voltage, but a short in any sensor on the same circuit can pull down the voltage for all of them.
The code does not always mean the PCM is bad; a simple chafed wire behind the engine block is a far more common cause than a failed PCM.
Some vehicles use the same reference voltage for sensors in different systems, such as the transmission and the engine, so a fault in one can set codes in multiple modules.
Intermittent low voltage can be caused by water intrusion after a car wash or heavy rain, leading to a code that sets only under wet conditions.
A poor ground connection for the sensor return circuit can mimic a low reference voltage, so always verify the sensor ground circuit before condemning the reference voltage supply.

Can I keep driving with P262D?

If the vehicle runs normally, you can drive it cautiously to a repair shop, but avoid heavy acceleration or towing. If the engine runs rough, stalls, or enters limp mode, stop driving and have it towed to prevent damage or unsafe operation.

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.