Faulty fuel injector on the affected cylinder (open coil or shorted winding); Damaged or chafed wiring harness between the PCM and the injector; Corroded or loose electrical connector at the injector or PCM; Internal failure of the PCM injector driver circuit; Short to ground or short to voltage on the driver circuit; Aftermarket or incorrect injector installed that does not match the PCM calibration

DTC codes / GM codes / P1680

P1680 · GMDriver 5

Q: What does code P1680 mean?

Driver 5. P1680 is a manufacturer-specific code stored by the powertrain control module (PCM) in GM vehicles when it detects a fault in the control circuit for Driver 5, which is one of the fuel injector driver outputs inside the PCM. The PCM monitors the electrical current through each injector driver and sets this code when the current falls outside the expected range, indicating an open circuit, short to ground, or short to voltage on that driver's circuit.

P1680 is a manufacturer-specific code stored by the powertrain control module (PCM) in GM vehicles when it detects a fault in the control circuit for Driver 5, which is one of the fuel injector driver outputs inside the PCM. The PCM monitors the electrical current through each injector driver and sets this code when the current falls outside the expected range, indicating an open circuit, short to ground, or short to voltage on that driver's circuit.

SystemPowertrain

Code typeGM specific

SeverityMedium

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Rough idle or misfire that may be intermittent
Engine hesitation or stumble during acceleration
Reduced fuel economy due to a misfiring cylinder
Possible rich or lean fuel trim readings depending on the failure mode
In some cases, the engine may enter limp mode or run poorly under load

Common causes, most likely first

Faulty fuel injector on the affected cylinder (open coil or shorted winding)
Damaged or chafed wiring harness between the PCM and the injector
Corroded or loose electrical connector at the injector or PCM
Internal failure of the PCM injector driver circuit
Short to ground or short to voltage on the driver circuit
Aftermarket or incorrect injector installed that does not match the PCM calibration

How to diagnose and fix it

Connect a scan tool and record all stored codes, freeze-frame data, and injector balance rates to confirm which cylinder is affected
Inspect the injector harness and connector at the affected cylinder for chafing, corrosion, or loose pins
Measure the resistance of the affected fuel injector with a multimeter and compare to specification
Check the driver circuit for shorts to ground or voltage using a wiring diagram and multimeter
Perform an injector balance test or swap the injector with a known-good cylinder to see if the code follows
If the circuit and injector test good, check for PCM software updates or internal driver failure
Replace the faulty injector or repair the wiring as needed, then clear codes and verify the repair with a test drive

What most technicians miss on P1680

A failed injector driver inside the PCM is less common than a bad injector or wiring, so always rule out the injector and harness before condemning the computer.
The code can be set by an intermittent connection that only acts up when the engine is hot or vibrating, so a wiggle test of the harness while monitoring injector data is often necessary.
Aftermarket injectors with incorrect resistance can trigger P1680 even though they physically fit, so verify the part number against the GM catalog.
A shorted injector can damage the PCM driver, so replacing only the injector without checking the driver circuit may lead to a repeat failure.
This code is often stored alongside misfire codes for the same cylinder, but the misfire code alone does not confirm the driver circuit is at fault.

Can I keep driving with P1680?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because a misfiring cylinder can overheat the catalytic converter. If the engine runs very rough or flashes the check engine light, stop driving and have it towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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