P20E2 code meaning
Exhaust Gas Temperature Sensor 1/2 Correlation (Bank 1)
Powertrain system Generic code P20xx codes Check engine light
What P20E2 means
P20E2 flags that bank 1 exhaust temperature sensors 1 and 2 disagree at a moment when both should show nearly the same value. Sensor 1 usually sits ahead of the oxidation catalyst and sensor 2 behind it. GM runs this check on the 6.6 L Duramax LML/LGH (table 15OBDG09) and on the diesel of table 15OBDG04: after at least 28,800 s (8 h) with the engine off, the two readings captured at start-up are compared, and a gap above a limit taken from a look-up table counts as a Type B fault, so the MIL lights after two failing trips. A sensor that is offset but still inside its valid voltage window passes the circuit checks P0544 and P2031–P2033 and is only caught here. Drivers rarely notice more than the lamp, although GM blocks some regeneration functions while this code is active.
P20E2 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P20E2
- Malfunction indicator lamp on, often with no change in driving
- Particulate filter regeneration delayed or blocked
- Code returns after a long parking period
Common causes of P20E2
- Most likelyExhaust temperature sensor 1 or 2 drifted or aged (offset reading)
- PossibleCorroded or loose connector adding resistance to one sensor signal
- Less likelySensors swapped or a non-matching replacement part installed
- Less likelyEngine control software needing an update
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Exhaust gas temperature sensorWiring harness
What each part of P20E2 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 0 | Area: fuel and air metering and auxiliary emission controls. |
| E2 | The exact fault in that area. |
What to do next
- Note P20E2 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P20E2
What does P20E2 mean?
P20E2 means "Exhaust Gas Temperature Sensor 1/2 Correlation (Bank 1)". P20E2 flags that bank 1 exhaust temperature sensors 1 and 2 disagree at a moment when both should show nearly the same value. It is a generic code, so it means the same on every make.
Is it safe to drive with P20E2?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P20E2 fail an emissions test?
Yes, it can. P20E2 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P20E2 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P20E2 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.