Exhaust Gas Temperature Sensor 1, Circuit Low
This code indicates a low voltage from the exhaust gas temperature sensor 1.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The exhaust gas temperature sensor measures how hot the exhaust gases are. When it reports a voltage that’s too low, it usually means there's a wiring issue or the sensor is bad.
What the computer is actually seeing
The engine control module expects the exhaust gas temperature sensor to produce a voltage between 0.5V and 4.5V based on exhaust temperature. If the voltage drops below 0.5V, it triggers this fault code.
What a healthy reading looks like
Voltage from the sensor should range from 0.5V (low temperature) to 4.5V (high temperature).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the exhaust gas temperature sensor and wiring for physical damage or disconnection.
- 22. Measure the voltage at the exhaust gas temperature sensor connector with the ignition on (engine off). Expected voltage should be between 0.5V and 4.5V.
- 33. If voltage is low (below 0.5V), inspect the wiring from the sensor to the ECM for shorts or opens.
- 44. If wiring is good, replace the exhaust gas temperature sensor and retest.
- 55. Clear the fault codes and perform a test drive to see if the code returns.
Common causes
- Faulty exhaust gas temperature sensor
- Wiring issues or harness damage
- Poor connector contact or corrosion
- Open circuit in the signal wire
- Grounding issues
- Faulty engine control module
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but it’s recommended to fix it soon as it can affect emissions.
Will this code come back after repairs?
If the underlying issue is resolved (good wiring, new sensor), it shouldn't come back.
Why is this code paired with other SPN codes?
Other SPN codes relate to related systems, like additional temperature sensors or related components.
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