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 P1421 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.
The Engine Control Module (ECM) controls ignition timing and engine idle speed when the engine is started with pre-warming up condition. This control promotes the activation of three-way catalyst by heating the catalyst and reduces emissions. The Diagnostic Trouble Code (DTC) will be set when the ECM does not control ignition timing and engine speed properly when the engine is started with prewarming up condition.
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