2012 GMC Sierra 1500 Problems: 12 Known Issues

On the 2007-2021 GMC Sierra 1500, p0016 means the crankshaft and Bank 1 intake camshaft are out of sync beyond tolerance. On the 5.3L V8 Sierra 1500 this is a signature failure because of two engine-specific problems: (1) the timing chain stretches over time — accelerated by AFM lifter debris and extended oil-change intervals — retarding cam timing until correlation exceeds threshold; and (2) the cam actuator (VVT) solenoid or phaser sticks. The AFM V8s are also known for oil consumption, and low/dirty oil starves the phasers and clogs solenoid screens, which both triggers P0016 and worsens chain wear. This is more serious than the related P0011: a severely stretched chain can jump a tooth and cause piston-to-valve contact, so continued driving is risky.

On the 2007-2022 GMC Sierra 1500, p0011 means the Bank 1 intake camshaft is timed more advanced than the ECM commanded — the phaser is stuck/biased advanced. On the Sierra 1500 5.3L/6.2L, the dominant cause is a VVT (camshaft actuator) solenoid whose internal screen has clogged with oil sludge or AFM debris, jamming the plunger so oil pressure to the phaser can't be modulated. GM acknowledges sticking/binding solenoids in PIs such as PIP5130K and PIP5855. Low or incorrect-viscosity oil is a very common trigger, so oil condition is always checked first. Because AFM lifter wear sheds metal into the oil, that debris circulates and clogs the solenoid screens — tying P0011 directly to the trucks' oil-consumption reputation. Drivers report rough running, and in worse cases stalling when slowing to a stop.

On the 2007-2018 GMC Sierra 1500, p0700 itself is only a flag: the Transmission Control Module has stored one or more transmission faults and is requesting the MIL. On Sierra 1500s with the 6L80 (and 6L90 on heavier variants) 6-speed automatic, the notable design issue is that the TCM is integrated into the valve body as a TEHCM (transmission electro-hydraulic control module), bolted inside the pan and sitting in 180-250°F fluid. Repeated heat cycling degrades the module and its integrated pressure switches and solenoids. When the TEHCM or a shift/pressure-control solenoid begins to fail, it sets specific sub-codes (e.g., P2534, P0742, P0761) plus the umbrella P0700, and the truck can exhibit harsh or missed shifts, slipping, or limp mode. Critically, on the 6L80/6L90 the solenoids are over-molded into the non-serviceable TEHCM and generally can't be replaced individually.

On the 2007-2017 GMC Sierra 1500, on the 5.3L V8 Sierra 1500, P0420 sets when the downstream (post-cat) O2 sensor tracks the upstream sensor too closely, meaning the Bank 1 catalytic converter is no longer scrubbing exhaust efficiently. The distinctive part on these trucks: the converter frequently dies prematurely from an upstream cause rather than age. Active Fuel Management (AFM) V8s burn oil past the lifters/rings, and that oil ash slowly poisons the catalyst substrate. GM TSB #16-NA-111 also documents a lesser-known trigger: a poor air-filter-housing seal lets abrasive dirt bypass the filter, wearing the O2 sensors and clogging the cat from the inside. Broken exhaust manifold bolts (a chronic GM V8 issue) create leaks that mimic P0420. Aftermarket cats have a poor track record here and often re-trigger the code within months.

On the 2007-2018 GMC Sierra 1500, p0430 is the Bank 2 counterpart to P0420 and, on the Sierra 1500 V8, points to the driver-side (Bank 2) catalytic converter falling below efficiency threshold. The mechanism is identical to Bank 1: the rear O2 sensor voltage begins mirroring the front sensor, so the ECM concludes that bank's cat can no longer store/release oxygen. The specific pattern on these trucks is that the underlying killer is usually AFM-related oil consumption or a lazy/aged rear O2 sensor rather than a defective converter out of the box. Owners commonly report P0430 (or both P0420 and P0430) returning even after installing new aftermarket converters — a well-documented frustration on GM-Trucks and SilveradoSierra forums — because the root cause (oil burning, exhaust leak, or a slow O2 sensor) was never corrected.

On the 2007-2018 GMC Sierra 1500, p0442 on the Sierra 1500 is a small EVAP leak detected during the ECM's key-off/idle vacuum test. On these trucks the two most common real-world causes are a loose, worn, or cracked gas cap seal (the cheapest fix and always the first check) and — a documented GM issue (TSB 15-NA-019) — the fuel tank filler vent hose connector cracking, which allows vapor to escape and sets P0442 (and sometimes P0455). The vent hose fracture is addressed by replacing the vent hose assembly (part No. 22802073 on 2013-2015 models). The EVAP purge valve (engine bay) and vent solenoid (near the tank) can also weep. Drivers often notice a faint fuel odor and the CEL, with no drivability change.

On the 2007-2023 GMC Sierra 1500, p0455 indicates a large (gross) EVAP leak — the ECM cannot pull or hold vacuum in the evaporative system at all. On the Sierra 1500 the classic causes are a completely missing/unsealed gas cap, a stuck-open or failed EVAP vent solenoid (mounted under the truck near the fuel tank/spare tire, where it's exposed to road spray, dirt, and corrosion), and a cracked or disconnected vapor/vent hose. Because the vent solenoid sits at the canister under the bed, water intrusion and corrosion cause it to stick open, which the ECM reads as a wide-open system; a tell-tale symptom is the fuel nozzle repeatedly clicking off during refueling. The filler vent hose connector fracture noted in GM literature can also escalate to P0455. Symptom-wise the driver usually sees only the CEL, sometimes a fuel smell, and no performance loss.

On the 2000-2013 GMC Sierra 1500, sierra owners across both GMT800 and GMT900 generations frequently report small electric HVAC actuators stripping internal gears or losing calibration. The result is a repetitive clicking or tapping noise from the dash, air stuck on defrost or floor, or one side blowing hot while the other blows cold. This is one of the most common non-drivetrain complaints on these trucks and is heavily documented in owner forums and repair databases.

On the 2007-2013 GMC Sierra 1500, owners of 2007-2013 Sierra 1500 trucks commonly report the upper dash cracking near the passenger airbag area and around defrost vents, especially in hot climates. While primarily a cosmetic and rattling issue, some owners also complain that broken plastic edges and loose pieces worsen over time. The problem is widely discussed in owner communities for GMT900 GM trucks and appears repeatedly in complaint databases.

On the 1999-2013 GMC Sierra 1500, front wheel hub bearing assemblies on Sierra 1500 trucks commonly wear out, especially on 4WD models and trucks used with larger tires or in rough conditions. Owners report humming or growling that changes with speed, looseness in the front wheel, and in some cases ABS warnings or low-speed ABS activation because the wheel speed sensor is integrated into the hub. This is a frequent repair item across both GMT800 and GMT900 generations.

On the 2007-2013 GMC Sierra 1500, gMT900 Sierra trucks are well known for failing door lock actuators, often starting with one door that unlocks weakly or only works intermittently before additional doors fail. Owners report the key fob cycling the locks while one or more doors remain stuck, requiring manual operation from inside. The issue is heavily documented across GM full-size truck forums and complaint records.

On the 2007-2019 GMC Sierra 1500, on the Sierra 1500, P0128 means the coolant did not reach the expected regulating temperature within the time/airflow the ECM predicted — almost always a thermostat stuck open (or partly open) so the engine runs too cool. The GM thermostat on the 5.3L/6.2L is integrated into a plastic housing on the engine, and the common failure is the thermostat losing its ability to close, letting coolant circulate continuously. Drivers notice the temp gauge sitting low, weak or slow-to-warm cabin heat (especially in winter), and worse fuel economy because the ECM stays in open-loop enrichment longer. A stuck-open thermostat is by far the most frequent cause; a failed/biased coolant temperature sensor is the secondary suspect and should be verified with live data before parts are thrown at it.