P2428 indicates the exhaust gas temperature (EGT) sensor on Bank 1 is reading a temperature higher than expected during normal operation. The EGT sensor monitors post-catalytic converter temperature to protect the converter and ensure proper emissions control. When readings exceed the manufacturer's threshold, this code is triggered.
The exhaust gas temperature sensor itself has failed or is providing inaccurate readings due to internal degradation, contamination, or wiring issues.
An exhaust leak (cracked manifold, loose pipe, damaged gasket) upstream of the EGT sensor can introduce outside air and cause abnormal temperature readings.
A consistently rich condition caused by faulty fuel injectors, high fuel pressure, or a malfunctioning MAF sensor can lead to elevated exhaust temperatures.
A partially clogged or inefficient catalytic converter can cause excessive backpressure and abnormal EGT readings.
Corroded, damaged, or shorted wiring in the EGT sensor circuit can cause false high temperature readings.
The powertrain control module may have an internal fault affecting EGT sensor signal processing, but this is uncommon and should be diagnosed only after all other causes are ruled out.
Driving is possible for short distances, but prolonged operation with elevated exhaust temperatures can damage the catalytic converter or other exhaust components. The issue should be diagnosed promptly.
Some technicians may recommend PCM replacement as a first step, but this is rarely the cause of P2428. The EGT sensor, wiring, exhaust leaks, and rich fuel conditions are far more common. PCM replacement should only be considered after all other possibilities are thoroughly investigated.
Costs vary significantly depending on the root cause. A faulty EGT sensor typically costs less in parts than diagnosing and repairing a rich fuel condition or exhaust leak. Labor costs depend on sensor location, which can require significant disassembly on some vehicles.
No. Once P2428 is set, it will not clear on its own. The underlying condition causing the high temperature reading must be identified and corrected to prevent potential catalytic converter damage.