P2033 Code: Exhaust Gas Temperature Circuit High (Bank 1 Sensor 2)
Is your DPF warning light on? Code P2033 means the ECU thinks your exhaust sensor is unplugged. Here is how to find the broken wire before your filter clogs.
1. What Does P2033 Mean?
The code P2033 stands for "Exhaust Gas Temperature (EGT) Sensor Circuit High Bank 1 Sensor 2."
This does not necessarily mean the temperature is high. It means the Voltage signal returning to the ECU is pegged at the maximum limit (usually 5 Volts). For most car computers, "5 Volts" is the code for "Open Circuit" or "Unplugged."
Basically, the ECU is listening for the sensor, but it hears nothing but static.
⚡ High Voltage = Broken Wire?
Understanding the electrical signal helps you fix it faster:
- P2032 (Circuit Low): Usually means "Short to Ground" (wires touching metal). Read P2032 Guide.
- P2033 (Circuit High): Usually means "Open Circuit" (broken wire, unplugged, or melted connector).
If you aren't sure where Sensor 2 is located, check our P2031 General Guide.
3. Why Is The Circuit "High"?
The EGT sensor lives in a hostile environment under the car. Common reasons for P2033 include:
- Broken Wire (The #1 Cause): Vibration causes the thin wires inside the sensor pigtail to snap internally. The sensor looks fine on the outside, but electricity cannot pass through.
- Melted Connector: The plastic plug is often located too close to the exhaust pipe. If the heat shield falls off, the connector melts, causing the pins to disconnect.
- Sensor Failure: The internal Thermistor element cracks from extreme thermal cycling (hot/cold), creating an open circuit.
4. Diagnosis: Graph the Voltage
You can verify if the circuit is truly open using the iCarsoft CR Eagle.
The "Unplug" Test Verification:
- Connect CR Eagle: Plug it into the OBD2 port.
- Live Data: View EGT Bank 1 Sensor 2 (Voltage or Temp).
- Observe: It is likely pegged at 5V (or a fake default temp like 1800°F).
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The Test: Unplug the sensor.
- If the reading stays the same (High/5V), the wiring from the ECU to the plug is likely fine, and the sensor itself was the "Open Circuit." Replace the Sensor.
- If the reading changes (unlikely for P2033), you have a complex wiring issue.
- Advanced: Use a jumper wire to bridge the two pins on the harness side. The voltage should drop to 0V. If it does, the wiring is perfect.
5. Inspect Hidden Wiring with Videoscope
Tracing EGT wires is difficult because they are routed over the transmission and behind heat shields. Use the CR Eagle's Built-in Videoscope to find the damage.
- Snake the Camera: Feed the 5.5mm probe along the EGT wiring harness.
- Look for Melting: Check if the wire insulation has melted against the exhaust manifold.
- Look for Breaks: Check for wires chewed by rodents (a common issue on top of the fuel tank/exhaust).
- This saves you from getting burnt by trying to feel the wires with your hands!
See What You Can't Touch
The iCarsoft CR Eagle is the ultimate tool for exhaust diagnostics. Use the 10.1-inch screen to graph sensor voltage and the Videoscope to inspect melted wiring in tight spaces.
- 10.1" Touchscreen: Clear view of electrical graphs.
- Built-in Videoscope: Inspect exhaust sensors safely.
- 10,000mAh Battery: Diagnose all day without charging.
6. Frequently Asked Questions
Q: Will P2033 prevent DPF regeneration?
A: Yes. If the ECU thinks the exhaust temp sensor is broken (reading 5V), it will never start a regen cycle because it fears it might overheat the DPF. This will lead to a clogged filter very quickly.
Q: Can I just bypass the sensor?
A: No. The ECU needs accurate temperature data to control fuel injection during regeneration. Using a resistor to fake the signal will likely cause the DPF to fail or melt.
Q: Is Sensor 2 the one before or after the DPF?
A: Usually, Sensor 2 is located before the DPF (but after the Cat), or right at the DPF inlet. Always check your specific vehicle manual, as some manufacturers label them differently.
