Quick answer: The P0435 code indicates a catalyst temperature sensor circuit malfunction in Bank 2, Sensor 3. It affects the emissions control system and powertrain computer monitoring. This is a moderate priority issue that will not leave you stranded immediately, but it must be resolved before your next mandatory emissions inspection.
Seeing a Check Engine light on your dashboard can be stressful, especially when it points to an unfamiliar powertrain code. If your OBD-II scanner returns a P0435, it means your vehicle’s computer has detected an electrical fault in the exhaust temperature monitoring system on the passenger side of the engine. This article walks you through what causes this issue, how to diagnose it safely, and what you can expect to spend on repairs.
What Does P0435 Mean?
Modern vehicles use exhaust gas temperature (EGT) sensors to monitor the thermal state of the catalytic converter and ensure the emissions control system operates efficiently. Bank 2 refers to the side of the engine that does not contain cylinder number one, and Sensor 3 typically points to a specific temperature monitoring point downstream of the main catalyst. When the Powertrain Control Module (PCM) receives an erratic, implausibly high, or completely missing voltage signal from this sensor, it triggers the P0435 diagnostic trouble code and illuminates the dashboard warning light.
Symptoms
- Illuminated Check Engine light
- Failed vehicle emissions test
- Slightly decreased fuel efficiency over time
- No noticeable change in engine drivability or performance
Possible Causes
Before you spend money on parts, keep in mind that the most common mistake is simply replacing the most expensive component first without proper testing. Always start with a thorough visual inspection.
- Damaged, melted, or corroded wiring harness near the exhaust system
- Loose or contaminated electrical connector at the EGT sensor
- Faulty exhaust gas temperature sensor on Bank 2, Sensor 3
- Exhaust leak upstream of the sensor altering temperature readings
- Internal software or hardware failure within the Powertrain Control Module
Check These Yourself Before Visiting a Mechanic
- Safely lift the vehicle and inspect the exhaust wiring near the rear of the catalytic converter for burns or chafing against the frame.
- Unplug the EGT sensor connector, check for moisture or corrosion inside the pins, and reconnect it securely.
How to Fix It
- Perform a visual and physical inspection of the EGT sensor wiring and connector, repairing any compromised wires found.
- Use a digital multimeter or scan tool to monitor live data and verify if the sensor reads ambient temperature when the engine is completely cold.
- Perform a smoke test or visual check to ensure there are no exhaust leaks blowing hot gas directly onto the wiring harness.
- Replace the faulty EGT sensor if electrical tests confirm the sensor internal circuit has failed.
- Reprogram or replace the Powertrain Control Module only if all wiring and sensor tests pass.
Estimated Repair Costs (2026)
| Job | Parts ($) | Labor ($) |
|---|---|---|
| Wiring Harness Repair | $10 – $50 | $75 – $150 |
| Exhaust Gas Temperature Sensor Replacement | $90 – $250 | $100 – $200 |
| Exhaust Leak Repair | $30 – $120 | $150 – $300 |
Note: these are 2026 estimates in US dollars; costs vary by make and model.
Frequently Asked Questions
Can I drive with the P0435 code?
Yes, you can usually drive short distances because this code relates to an emissions monitoring circuit rather than a critical engine failure. However, ignoring it can lead to degraded fuel economy and an automatic failure during your state emissions inspection.
How do I clear the P0435 code?
You can clear the code using any standard OBD-II scan tool plugged into your vehicle port. Keep in mind that if the underlying electrical fault or failed sensor is not repaired, the Check Engine light and P0435 code will return within a few driving cycles.
Will a clogged catalytic converter trigger P0435?
Usually no. While a failing converter can cause unusual exhaust temperatures, code P0435 specifically targets the electrical circuit performance of the temperature sensor itself rather than catalytic efficiency codes like P0420 or P0430.