Code
P2494
Generic
P — Powertrain
EGR Cooler Bypass Position Sensor Circuit Low Bank 1
Views:
UK: 15
EN: 27
RU: 17
AI status
Completed
Completed
100%
Causes
- Damaged, chafed or corroded wiring or connector to the EGR cooler bypass position sensor (Bank 1)
- Short to ground in the sensor signal circuit
- Faulty EGR cooler bypass position sensor
- Stuck or mechanically seized EGR cooler bypass valve/actuator
- Coolant or debris intrusion into sensor or actuator assembly
- PCM/ECM internal fault or poor ground/reference voltage
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Reduced engine performance or derate in some vehicles
- Rough idle or hesitation when EGR system is active
- Increased NOx emissions or failed emissions test
- Possible coolant leak symptoms if sensor/actuator contaminated
What to check
- Read freeze frame and live data with a scan tool; confirm P2494 and note conditions (load, temp) when it set
- Perform visual inspection of EGR cooler bypass actuator, wiring harness and connectors for damage, corrosion or coolant contamination
- Backprobe sensor connector and observe live voltage/position values while operating actuator (if possible)
- Check reference and ground circuits at the sensor (typically 5V reference and ground)
- Perform wiggle test on harness while monitoring sensor signal for intermittent changes
- Inspect mechanical operation of EGR cooler bypass valve/actuator; ensure it moves freely
Signal parameters
- Position sensor is typically a 3-wire or 2-wire potentiometer/hall-style device: expect a 0–5.0 V signal range from low (closed) ≈0.3–1.0 V to high (open) ≈4.0–4.8 V (varies by design)
- Reference supply commonly 5.0 V; ground ≈0 V; sensor impedance varies by manufacturer
- On key-on engine-off you may see a defined rest voltage; during commanded movement the voltage should change smoothly without dropouts
Diagnostic algorithm
- Verify code and capture live data with scan tool. Note sensor voltage at rest and during commanded EGR bypass movement.
- Inspect harness and connector visually for corrosion, frayed wires, melted insulation or coolant contamination. Repair as needed.
- With ignition on, backprobe sensor connector: confirm 5V reference (if used), ground continuity to chassis, and measure signal voltage. Reference and ground must be stable.
- If reference or ground missing or out of range, trace and repair wiring or grounds. Repair connector or harness as required.
- If reference/ground OK but signal is low or stuck, disconnect sensor and measure sensor resistance per service info (or substitute by measuring signal while actuating). If sensor fails to change, replace sensor/actuator.
- Verify mechanical operation of the bypass valve: command actuator with scan tool (if supported) or apply appropriate bench voltage/air/vacuum per manufacturer procedure. Replace or clean valve if seized.
- After repairs clear codes and perform test drive or actuation cycle to confirm the sensor reports correct range and the DTC does not return.
- If all wiring and sensor check OK and fault persists, consider module input circuit test or ECM replacement as a last step (refer to vehicle-specific service information).
Likely causes
- Open or shorted signal wire (most common)
- Connector corrosion or poor ground at sensor
- Failed position sensor inside the EGR bypass actuator
- Mechanically stuck bypass valve preventing sensor from moving
- Coolant contamination or internal corrosion of the sensor
Fault status
Status
PCM detected a low (grounded or low-voltage) signal from the EGR cooler bypass position sensor circuit on Bank 1, indicating an electrical fault, sensor failure, or stuck bypass valve.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P2494
LAND ROVER
P — Powertrain
Recirculation gas cooler bypass position sensor escape - Low circuit - Bank 1
Views:
UK: 8
EN: 6
RU: 3
AI status
Completed
Completed
100%
Causes
- Damaged, chafed or corroded wiring or connector to the EGR cooler bypass position sensor (Bank 1)
- Short to ground in the sensor signal circuit
- Faulty EGR cooler bypass position sensor
- Stuck or mechanically seized EGR cooler bypass valve/actuator
- Coolant or debris intrusion into sensor or actuator assembly
- PCM/ECM internal fault or poor ground/reference voltage
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Reduced engine performance or derate in some vehicles
- Rough idle or hesitation when EGR system is active
- Increased NOx emissions or failed emissions test
- Possible coolant leak symptoms if sensor/actuator contaminated
What to check
- Read freeze frame and live data with a scan tool; confirm P2494 and note conditions (load, temp) when it set
- Perform visual inspection of EGR cooler bypass actuator, wiring harness and connectors for damage, corrosion or coolant contamination
- Backprobe sensor connector and observe live voltage/position values while operating actuator (if possible)
- Check reference and ground circuits at the sensor (typically 5V reference and ground)
- Perform wiggle test on harness while monitoring sensor signal for intermittent changes
- Inspect mechanical operation of EGR cooler bypass valve/actuator; ensure it moves freely
Signal parameters
- Position sensor is typically a 3-wire or 2-wire potentiometer/hall-style device: expect a 0–5.0 V signal range from low (closed) ≈0.3–1.0 V to high (open) ≈4.0–4.8 V (varies by design)
- Reference supply commonly 5.0 V; ground ≈0 V; sensor impedance varies by manufacturer
- On key-on engine-off you may see a defined rest voltage; during commanded movement the voltage should change smoothly without dropouts
Diagnostic algorithm
- Verify code and capture live data with scan tool. Note sensor voltage at rest and during commanded EGR bypass movement.
- Inspect harness and connector visually for corrosion, frayed wires, melted insulation or coolant contamination. Repair as needed.
- With ignition on, backprobe sensor connector: confirm 5V reference (if used), ground continuity to chassis, and measure signal voltage. Reference and ground must be stable.
- If reference or ground missing or out of range, trace and repair wiring or grounds. Repair connector or harness as required.
- If reference/ground OK but signal is low or stuck, disconnect sensor and measure sensor resistance per service info (or substitute by measuring signal while actuating). If sensor fails to change, replace sensor/actuator.
- Verify mechanical operation of the bypass valve: command actuator with scan tool (if supported) or apply appropriate bench voltage/air/vacuum per manufacturer procedure. Replace or clean valve if seized.
- After repairs clear codes and perform test drive or actuation cycle to confirm the sensor reports correct range and the DTC does not return.
- If all wiring and sensor check OK and fault persists, consider module input circuit test or ECM replacement as a last step (refer to vehicle-specific service information).
Likely causes
- Open or shorted signal wire (most common)
- Connector corrosion or poor ground at sensor
- Failed position sensor inside the EGR bypass actuator
- Mechanically stuck bypass valve preventing sensor from moving
- Coolant contamination or internal corrosion of the sensor
Fault status
Status
PCM detected a low (grounded or low-voltage) signal from the EGR cooler bypass position sensor circuit on Bank 1, indicating an electrical fault, sensor failure, or stuck bypass valve.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
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