Posts Tagged: P1400

Understanding the P1400 Code in GM Vehicles

What is the P1400 Code in GM Vehicles? If you have an engine coolant heater, read this GM service bulletin first GM defines a P1400 as Cold Start Emission Reduction Control System. That may sound like Greek to you, but there’s a method to their madness. A catalytic converter must warm up sufficiently to process excess hydrocarbons. One way to do that is to increase idle speed and retard timing during a cold start. So the computer commands those parameter on cold start up and then monitors this data: Engine … Read More