Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
The cost to diagnose the P1291 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.
Temperature rise from intake air heaters is monitored for first 15 seconds of engine operation. The P1291 code may be stored if initial Intake Air Temperature (IAT) sensor reading is 0-66°F (-17.8 to 18.8°C), Battery Temperature Sensor (BTS) and Intake Air Temperature (IAT) sensor are within 10°F of each other, time between end of preheat and engine run state is less than 30 seconds, engine is cranked for less than 5 seconds before engine starts, preheat is completed before engine starts, post-heat is active and no IAT sensor or intake air heater relay DTCs exist.
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