A flashing check engine light and a stumbling idle in a truck that's barely broken in is a special kind of annoying. The good news for third-generation Colorado owners: GM has published a pretty clear roadmap, and step one costs nothing but a little patience.
Which trucks this covers
The 2.7L four-cylinder turbo (GM engine code L3B, marketed as TurboMax from 2023) is the engine in the 2023 and newer Colorado. It also lives in the Silverado 1500, Sierra 1500 and Canyon, so bulletins usually list all four.
What GM's bulletins say
| Bulletin | Covers | Cause and fix |
|---|---|---|
| PIE0808 / PIE0808A (2024-2025) | 2023-2024 Colorado 2.7L | Check engine light with about two dozen injector and misfire codes, including P0300. GM first gathered field data, then pointed dealers to PIP6023. |
| PIP6023D (January 2026) | 2023-2026 Colorado 2.7L | Poor connection at fuel rail connector X160. Unplug, wait 60 seconds, reconnect, drive 10+ miles. If codes return, follow the normal diagnosis. |
| PIP6062 (May 2025) | 2023-2025 Colorado 2.7L | Engine wiring harness chafing where it touches the turbo heat shield or wastegate linkage. Symptoms range from misfires and reduced power to ABS/SES lights, CAN bus faults and even no-crank. Inspect and repair the harness. |
| Engineering info notice (2024) | 2023-2024 Colorado 2.7L | Check engine light with code P30BF. GM asked dealers not to repair it before contacting engineering. |
What you'll notice
- Check engine light, sometimes flashing (a flashing light means an active misfire)
- Rough idle or a stumble, especially on cold starts
- Hesitation when you get on the throttle
- A "reduced engine power" message
- Several unrelated warning lights at once (that pattern points toward the chafed harness in PIP6062)
One NHTSA complaint on a 2023 Colorado describes the truck dropping from 70 to 30 mph with the check engine and traction control lights on. The dealer diagnosed a cylinder misfire.
Easy things to do first
- Scan the codes. Write them all down, not just the first one. P0300 plus injector codes points at the connector or harness. A single-cylinder code like P0302 can point at a plug or coil on that cylinder.
- Note the conditions. GM's bulletin asks dealers to recreate what the customer saw (cold start, highway, under load).
- Don't clear codes before the dealer sees them if you're under warranty. Some bulletins tell techs not to clear them until engineering weighs in.
- Check for aftermarket add-ons. Tuners and plug-in modules near the harness can cause or hide problems.
When it really is spark plugs
Chevrolet's interval for plugs on this engine is long (about 97,500 miles), but owners quoted by SlashGear report plugs causing misfires much earlier on some L3B trucks. On a turbo engine, worn plugs are a common misfire source once you're past the wiring bulletins. Replacing them means pulling the engine cover and coils, so it's a reasonable DIY for some, but most owners let a shop do it.
What it costs
| Job | Model years | Likely cost |
|---|---|---|
| Bulletin connector reseat or harness repair, under warranty | 2023-2026 | Usually $0 (5-year/60,000-mile powertrain, 3-year/36,000-mile bumper-to-bumper) |
| Spark plug replacement | 2023-2026 Colorado | $259 to $344 (RepairPal) |
| Ignition coil, injector or harness repair out of warranty | 2023-2026 | Get a written quote after diagnosis |
What to ask the dealer
- "Did you check fuel rail connector X160 per PIP6023?"
- "Did you inspect the harness at the turbo heat shield and wastegate linkage per PIP6062?"
- "Which cylinders were misfiring, and what did you find on that cylinder?"
- "Is this covered under bumper-to-bumper or powertrain?"
Is it worth fixing?
Absolutely. This is a newer truck and the first fixes are cheap or free. Get it in while the warranty is fresh, make sure the bulletins are on the repair order, and keep every receipt.
More Colorado info is on the Chevrolet Colorado page. Shifts feeling rough too? Read our Colorado 8-speed shudder guide. Bulletin details and prices checked October 14, 2026.
