Code
P246E
Generic
P — Powertrain
Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 4
Views:
UK: 12
EN: 43
RU: 14
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between the EGT sensor and ECM (including chafing or corrosion)
- Poor or corroded connector pins at sensor or harness
- Failed or internally shorted EGT sensor (thermocouple, RTD, or sensor with heater)
- Blown fuse or failed driver/heater circuit in ECM (for sensors with heaters)
- Exhaust leaks or sensor physically damaged by heat or contamination
- Intermittent connection due to vibration or water intrusion
Symptoms
- Check Engine Light (MIL) illuminated
- Possible reduced engine power, limp-home mode, or derate on some vehicles
- Degraded aftertreatment performance or catalyst regeneration issues
- Poor fuel economy or increased emissions
- Fault may be intermittent (codes set on warming/cooling cycles)
What to check
- Scan tool: record freeze frame and live EGT data for Bank 1 Sensor 4 and compare to other EGT sensors
- Visual inspection of sensor, wiring harness, and connector for damage, corrosion, soot or signs of overheating
- Wiggle test harness/connectors while monitoring live data to reproduce fault
- Check for exhaust leaks near the sensor (manifold, flex pipe, joints, or downstream components)
- Measure continuity between sensor connector and ECM pin; check for short to battery and short to ground
- For sensors with a heater: check fuse/relay, measure heater supply voltage and control signal from ECM
Signal parameters
- EGT sensor outputs typically increase with exhaust temperature; expect a low signal when cold and a rising signal as temperature increases
- Thermocouple-style EGT: small millivolt output (mV) proportional to temperature; values vary by sensor design — verify with manufacturer data
- RTD-style EGT: resistance changes with temperature — check resistance vs. specified table
- Heater supply (if present): switched 12 V or PWM from ECM; heater resistance commonly in the low ohms to tens of ohms
- Typical confirmation: continuity < 5 ohms for heater circuit (vehicle-specific), open circuit indicates sensor/heater failure
Diagnostic algorithm
- Record code, freeze frame and confirm vehicle conditions when code set (engine temp, load, RPM).
- Perform a thorough visual inspection of Bank 1 Sensor 4 and harness; repair any obvious damage or corrosion and clear codes to retest.
- Check for exhaust leaks upstream or near the sensor that can affect readings; repair any leaks.
- Backprobe the sensor connector with a multimeter or oscilloscope while warming engine: verify signal behavior (mV or resistance) and compare to a known-good sensor or manufacturer spec.
- Inspect for short to power/ground and measure continuity from sensor connector to ECM pin. Replace harness or repair wiring if faults are found.
- If sensor has heater: with key on, measure heater supply and control; verify fuse/relay and ECM drive. If no supply or drive, test related fuses/relays and ECM outputs.
- If wiring and power/ground are good but signal is out of range or open, replace the EGT sensor and clear codes.
- After repair, perform road/drive cycle and confirm code does not return and that EGT readings behave normally across temperature range.
- If fault persists after replacing sensor and repairing wiring, consider ECU/PCM diagnostics or module programming as a last step.
Likely causes
- Damaged connector or corroded pins at Bank 1 Sensor 4
- Broken or shorted wiring in the harness to the rear/post catalyst sensor
- Failed EGT sensor (most common cause after visual/harness check)
- Heater circuit failure or ECM output fault (if sensor uses heater)
Fault status
Status
EGT sensor circuit fault detected on Bank 1 Sensor 4 — open/short/out-of-range or heater circuit issue.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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