B1089 GMC OBD2 specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.
When you fill your car with gas, the vapors in the tank get forced into a canister filled with activated charcoal. Also, on a hot day as the gas heats up and vaporizes, those same vapors push into the canister where they're stored. But the charcoal can only hold so much vapor. At some point it has to be emptied. The emptying process is called canister purge.
The crankshaft sensor signals the fuel injection computer or the ignition control when the cylinders are firing. This causes the ignition coil to provide a spark and the injector to inject fuel into each cylinder at the right time.If either sensor isn't working correctly, the car will run rough and the engine will be less efficient. In later car models, the car's computer can usually keep the vehicle running, but the engine warning light on the dashboard goes on to warn the driver.
B1089 meaning and repair processes are the same for all GMC models.
B1089 GMC Trouble Repair Process:
OBD 2 B1089 GMC code and tailpipe testing are two different approaches to identify vehicles in need of repair. The OBD system looks for broken or malfunctioning emissions control components while tailpipe tests sample a vehicle's exhaust to see if it is above or below certain prescribed limits. Given the robust nature of today's emissions control components, it is entirely possible for an individual component to malfunction without leading to an immediate increase in emissions at the tailpipe. In such cases, other components (like the catalyst) can temporarily compensate for the part that is broken however, these other components can only do double duty for so long before they, too, begin to malfunction. Because of its ability to monitor individual components, OBD is able to give motorists an early warning that repairs are needed; it is because of this early warning capability that OBD will sometimes fail vehicles that would otherwise pass a tailpipe test.
It works by having a slightly higher than normal opening temperature, which still works the same way as regular ones, but it also has a heating coil, which means the ECU can open the thermostat earlier and keep the engine slightly cooler.