P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1

P2428 code definition

A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one cylinder. A P2428 trouble code is also associated with trouble code P2429.

What the P2428 code means

A malfunction in the exhaust temperature sensor causes a variation in the voltage reading to the PCM from the sensors in the exhaust system. Any variation in the voltage exceeding the manufacturer's limitations causes a trouble code to be stored and the illumination of the Check Engine light.

What causes the P2428 code?

Some common causes of a P2428 trouble code include:

• Loose, broken, burned, and corroded wiring, terminals, or connectors

• A short in the exhaust gas temperature sensor

• A faulty exhaust gas temperature sensor

• A decrease in back pressure, most commonly caused by an aftermarket off road exhaust system

• A severe exhaust leak located upstream from the exhaust gas temperature sensor

• Engine overheating

What are the symptoms of the P2428 code?

The only indication of a P2428 trouble code is the stored code itself and an illuminated Check Engine light.

How does a mechanic diagnose the P2428 code?

To successfully diagnose a P2428 trouble code, the mechanic needs an advanced OBD-II trouble code scanner, a digital volt/ohmmeter, and an infrared thermometer with a laser pointer. To properly diagnose the code, the mechanic needs to perform the following:

• Visually inspect all of the wiring and connectors.

• Use the digital volt/ohmmeter to check the resistance of the exhaust gas temperature sensor.

• If initial voltage is within specifications, heat the resistor with a heat gun while leaving the leads of the digital volt/ohmmeter attached.

• Observe the resistance level of the sensor using an infrared thermometer to see if the temperature decreases smoothly.

• If the mechanic detects low voltage on the signal wire, disconnect the PCM connector and perform continuity testing using the digital volt/ohmmeter.

• After repairs are completed, retest the system to make sure the repairs are successful.

• Connect the advanced scanner to the diagnostic connector and make sure to record any stored codes, in addition to freeze frame data. This information can come in handy if there is an intermittent condition leading to the trouble code being stored.

• Clear the P2428 trouble code and test drive the vehicle to see if the code returns.

Common mistakes when diagnosing the P2428 code

A common misdiagnosis occurs when the mechanic mistakenly identifies the oxygen sensor as the exhaust gas temperature sensor. In this case, replacing the oxygen sensor does not fix the P2428 trouble code, with the problem persisting. In addition, make sure the engine does not have an overheating issue before diagnosing the code, as engine overheating could be the source of the problem.

How serious is the P2428 code?

Failure to repair a P2428 trouble code can lead to issues with the ignition timing or air/fuel ratio in an attempt by the PCM to protect the catalytic converter from the high temperatures produced. This, in turn, can lower fuel efficiency, as well as indicate more serious engine problems, especially if the code is caused by an overheating engine.

What repairs can fix the P2428 code?

To repair a condition associated with a P2428 trouble code, the mechanic should do the following:

• Make sure the vehicle does not have an overheating problem. If that is the case, fixing this condition could clear up the problem causing the code.

• After inspecting all wiring and connectors, replace damaged, worn, corroded or shorted wires and connectors.

• If the exhaust gas temperature sensor is faulty after subsequent testing with the digital volt/ohmmeter and heat gun, the mechanic should replace it as well.

• The PCM might also be at fault and should be tested as well. After testing with the digital volt/ohmmeter, if the PCM does prove at fault, the mechanic needs to replace the PCM. The, after reprogramming it, the mechanic needs to retest the system.

Additional comments for consideration regarding the P2428 code

Before removing and replacing any emission-related components, the mechanic should make sure to check local, state, and federal laws to ensure they are in compliance.

Need help with a P2428 code?

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