Code
P246A
Generic
P — Powertrain
Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic Bank 2 Sensor 3
Views:
UK: 19
EN: 37
RU: 22
AI status
Completed
Completed
100%
Causes
- Damaged or chafed EGT sensor wiring harness (intermittent connection)
- Corroded, loose, or heat-damaged connector at the sensor or PCM
- Failed EGT sensor (internal fault or thermistor/thermocouple degradation)
- Poor or intermittent ground for sensor or PCM
- Exhaust leak or mechanical damage near the sensor causing abnormal temperatures or vibration
- High-resistance splice or connector pin backout
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Intermittent or inconsistent EGT readings in live data (spikes, dropouts, or noise)
- DPF regeneration faults or inability to complete regen (if equipped)
- Possible reduced engine protection features or limp mode during some conditions
- Rarely, observable exhaust odor or visible damage near the sensor
What to check
- Scan for freeze-frame and related codes (other EGT or DPF codes) and record live data during reproduction
- Visual inspection of sensor, connector, and wiring routing near the exhaust for heat damage, chafe, soot, or physical damage
- Wiggle test harness and connector while monitoring live EGT data to try to reproduce the intermittent behavior
- Backprobe connector with a scan tool or multimeter to observe signal response while warming the exhaust (safe heat source) or during controlled engine load
- Check connector pins for corrosion, bent pins, or poor seating and inspect for signs of water or soot ingress
- Measure continuity and resistance between the sensor connector and PCM pin for intermittent opens/high resistance
Signal parameters
- Sensor signal should be stable and change smoothly with increasing exhaust temperature (no sudden jumps or frequent noise)
- Sensor output type varies by design: thermocouple (mV) or thermistor/voltage (0–5 V). Expect a low signal at ambient that increases with temperature.
- Heater circuit (when present) should show battery voltage when commanded and not be intermittently switching or open
- An open circuit presents as no change in signal with temperature; a short to ground or 12V will show pegged/invalid voltage
- Intermittent faults typically appear as spikes, sudden drops to zero, or repeated brief loss of signal in live data
Diagnostic algorithm
- Retrieve and record freeze-frame data and all stored/related codes. Note operating conditions when the code set.
- Inspect the sensor, connector, wiring, heat shields, and nearby exhaust components for external damage, chafing, or signs of heat deterioration.
- With a capable scan tool, monitor the Bank 2 Sensor 3 EGT live data while performing a controlled load or warm-up to see if the signal behaves erratically.
- Perform a wiggle test of the harness and connector while observing live data to try to reproduce the intermittent condition. If reproduced, suspect wiring/connector.
- Backprobe the sensor connector and check: signal voltage (or mV), continuity to PCM, and ground integrity. Compare behavior when heating the sensor area (use a safe heat source—do not use an open flame).
- If the sensor has a heater, verify heater supply and control: with key on, check for battery voltage at the heater supply, and when aiming a regen or commanded heater ON, confirm current draw or voltage change as expected.
- If backprobe/continuity checks are good but signal remains intermittent, disconnect the sensor and measure its resistance or output per manufacturer procedure (if available). Replace if readings are out of expected range or vary erratically when heated/cooled.
- Repair any damaged wiring, corrosion, or poor connections. Replace pigtails/terminals or re-route harness away from high heat where necessary. Use heat-resistant sleeving and proper clamps.
- After repair or component replacement, clear codes and perform a verification drive or regeneration attempt while monitoring live data to confirm stable sensor behavior and that the code does not return.
- If the fault persists after sensor/harness repair, consider PCM connector inspection and, as a last resort, PCM testing by a specialist.
Likely causes
- Wiring or connector damage near the exhaust (heat-related deterioration or chafing)
- Sensor failure from long-term exposure to soot/contaminants or thermal cycling
- Loose/corroded connector producing intermittent contact
- Intermittent ground or poor connector pin contact
Fault status
Status
Exhaust Gas Temperature Sensor Circuit Intermittent/Erratic — Bank 2 Sensor 3. Sensor signal is unstable or erratic; inspect sensor, wiring and connectors.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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