The 2025 Terrain is a clean-sheet redesign, but the engine is a familiar one: GM's 1.5-liter turbo four, called the LSD, rated at 175 hp in earlier Terrains. Because it's shared with the Chevy Equinox, problems found on one usually show up in bulletins for both. Here's what's been published so far.
1. Hesitation, chuggle, surge or misfire
This is the one most new owners notice. GM Preliminary Information PIP6071A covers 2023-2026 Terrain (and Equinox) with the 1.5L turbo. Symptoms: engine chuggle, surge, hesitation on acceleration, or misfire, with codes P0300, P2097, P2251 and/or P223C.
GM's suspected cause is a misaligned position 1 oxygen sensor (the upstream sensor). Dealers replace that sensor and inspect the catalytic converter for damage while it's out. GM Authority reports the problem is more noticeable on units built before May 27, 2025.
2. Sudden loss of power
GM bulletin PIP5927B covers 2023-2025 Terrain (and Equinox) with the 1.5L turbo. Symptoms: loss of engine power with one or more of codes P0237, P0101, P1101 and P0299. GM Authority notes the same issue was reported earlier on 2018-2022 Terrains.
The likely culprit is the charge air inlet pipe where it meets the turbo. Techs first check for a split or shredded anti-abrasion sleeve, then for splits in the hose itself. A split hose can swell, confuse boost control, or leak air. If the hose is damaged and the codes are there, the dealer replaces the charge air inlet pipe assembly.
There's also a newer item for brand-new stock. PIP6080 (August 2025) covers 2026 Terrain and Equinox with the 1.5L, all VINs, reporting "lack of acceleration or low power" on unsold units. Cause wasn't determined yet. GM's interim step was to disconnect the battery for several minutes and re-evaluate, and send data to engineering.
3. Running hot and the AC quits
GM bulletin 26-NA-210 covers 2024-2026 Terrain with the 1.5L turbo. Symptoms: engine overheating, cooling fan not working, AC that stops working, and code P0494 (cooling fan speed too low). The electric fan has its own built-in control module, and it can fail internally.
The fix is a new fan motor (the latest service part includes an internal update). The fan sits behind the charge air cooler, condenser and radiator, so it's a real service job, not a quick swap. GM Authority stresses that not every Terrain has a bad fan.
Older Terrains: the PCV and oil issue
If you're shopping used, know that the 2018-2024 Terrain with the same 1.5L family has a widely reported PCV (crankcase ventilation) problem. Au7o's owner-report summary describes oil in the intercooler pipes, blue or white smoke, coolant loss with no visible leak, and boost or misfire codes. The usual repair is an updated valve cover with a revised PCV diaphragm, plus cleaning oil out of the intake. Nothing has been published tying this to the 2025 redesign yet.
Quick symptom guide
| What you notice | Codes | Bulletin | Likely fix |
|---|---|---|---|
| Chuggle, surge, hesitation, misfire | P0300, P2097, P2251, P223C | PIP6071A | Replace upstream O2 sensor, inspect catalyst |
| Low power, sluggish under boost | P0237, P0101, P1101, P0299 | PIP5927B | Replace charge air inlet pipe |
| Overheating, AC quits | P0494 | 26-NA-210 | Replace cooling fan |
| New 2026 with weak acceleration | None specific | PIP6080 | Battery reset, data to GM |
What it costs
A 2025 or 2026 Terrain is still inside GM's factory bumper-to-bumper and powertrain coverage, so these repairs should cost you nothing at a GMC dealer. If you're out of warranty or using an independent shop, RepairPal estimates an oxygen sensor at $331-$418 for a 2025 Terrain and $285-$346 for a 2026. For the charge air pipe and cooling fan, ask for a written quote.
Easy things to do first
- Get the codes read. Auto parts stores will often scan for free. Write the codes down before anyone clears them.
- Note when it happens. Cold start? Only under load? Only at low speed? Dealers fix faster when you can describe it.
- Check for recalls at nhtsa.gov/recalls. As of this writing, NHTSA lists no engine recall for the 2025 Terrain.
- Use the right fuel and oil listed in your owner's manual.
What to ask the dealer
- "Do PIP6071A, PIP5927B or 26-NA-210 apply to my VIN and build date?"
- "Which codes are stored right now?"
- "Was the catalytic converter checked when the O2 sensor was replaced?"
- "Can I get a copy of the repair order showing the bulletin used?"
Is it worth fixing?
On a new Terrain under warranty, it's not even a question. Make the appointment, cite the bulletin, and keep your paperwork. Repeat visits for the same problem also matter if you ever need to make a lemon law claim.
More Terrain help lives on the GMC Terrain page. Won't start, just clicks? See our Terrain no-start guide. Bulletins and prices checked October 14, 2026.
