What Does P242E Mean?
The EGT sensor 3 on bank 1 signal is unstable, fluctuating rapidly, or cutting in and out intermittently. This indicates an unreliable connection or failing sensor element.
Common Causes
35%
Loose or corroded sensor connector with intermittent contact
30%
Internally failing EGT sensor with intermittent element
25%
Damaged wiring harness with intermittent short or open
10%
Poor ground connection causing signal interference
Diagnostic Steps
1
Step 1: Wiggle test the sensor connector and wiring while monitoring live data for signal dropout
2
Step 2: Inspect connector terminals for corrosion, bent pins, or inadequate tension
3
Step 3: Check wiring harness routing for contact with hot exhaust components or sharp edges
4
Step 4: Monitor sensor voltage/resistance while tapping sensor body gently to detect internal failures
5
Step 5: Verify all ground connections are clean and tight, including ECM grounds
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The EGT sensor 3 on bank 1 signal is unstable, fluctuating rapidly, or cutting in and out intermittently. This indicates an unreliable connection or failing sensor element.
The most common cause of P242E (Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 1 Sensor 3) is: Loose or corroded sensor connector with intermittent contact
Typical repair costs for P242E range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive but intermittent faults can cause unpredictable emission system behavior. Address promptly to prevent component damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P242E to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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