Chafed or damaged fuel pump wiring harness near the tank or under the rear seat; Corroded or loose ground connection at the fuel pump module or chassis; Failed fuel level sensor with an internal short to ground; Water intrusion into the fuel pump connector or wiring loom; Faulty fuel pump module assembly with a shorted internal circuit; Damaged PCM ground circuit or poor engine-to-chassis ground strap

DTC codes / GM codes / P1215

P1215 · GMGround Fault Detection Indicated

Q: What does code P1215 mean?

Ground Fault Detection Indicated. P1215 on a GM vehicle means the powertrain control module (PCM) has detected a ground fault in a monitored circuit, typically the fuel pump or fuel level sensor wiring, indicating an unintended path to ground or an open ground reference. The PCM compares voltage on the circuit to expected values and flags the code when the signal falls outside the normal ground-referenced range.

P1215 on a GM vehicle means the powertrain control module (PCM) has detected a ground fault in a monitored circuit, typically the fuel pump or fuel level sensor wiring, indicating an unintended path to ground or an open ground reference. The PCM compares voltage on the circuit to expected values and flags the code when the signal falls outside the normal ground-referenced range.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Intermittent or complete fuel pump failure causing a no-start or stall
Erratic or inaccurate fuel gauge readings
Rough running or hesitation if the fault affects fuel delivery
Blown fuse or fuel pump relay clicking repeatedly

Common causes, most likely first

Chafed or damaged fuel pump wiring harness near the tank or under the rear seat
Corroded or loose ground connection at the fuel pump module or chassis
Failed fuel level sensor with an internal short to ground
Water intrusion into the fuel pump connector or wiring loom
Faulty fuel pump module assembly with a shorted internal circuit
Damaged PCM ground circuit or poor engine-to-chassis ground strap

How to diagnose and fix it

Inspect the fuel pump wiring harness and connector for chafing, corrosion, or water intrusion
Check and clean all ground connections related to the fuel pump and PCM, including chassis grounds
Measure resistance from the fuel level sensor signal circuit to ground to detect a short
Disconnect the fuel pump module and check for a short to ground on the harness side
Test the fuel pump module for internal shorts using a multimeter and wiring diagram
Repair or replace damaged wiring, connectors, or the fuel pump module as needed
Clear the code and verify the repair with a test drive and live data scan

Ground faults often hide in plain sight

A ground fault can be caused by a poor ground connection rather than a direct short, so voltage drop testing is more reliable than simple continuity checks.
The fuel level sensor circuit is frequently the culprit because it shares a ground with the fuel pump, and a failing sensor can set P1215 without affecting drivability.
Aftermarket fuel pumps with incorrect resistance values can trigger P1215 even when wiring is perfect, so always compare sensor resistance to OEM specifications.
P1215 can be set by a loose battery ground or engine ground strap, which corrupts the PCM's ground reference and mimics a fuel system fault.
Inspect the wiring under the rear seat and at the fuel tank for rodent damage or pinched harnesses, especially on trucks and SUVs used in rural areas.

Can I keep driving with P1215?

If the engine runs normally and only the light is on, you can drive short distances to a repair shop, but avoid hard acceleration or long trips. If the engine stalls, hesitates, or the fuel gauge behaves erratically, stop driving and have the vehicle towed to prevent a breakdown.

Tools that help

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