OBD-II code · Powertrain (generic, extended)
P2494 EGR Cooler Bypass Position Sensor Circuit Low Bank 1
Same as P2492 with the signal voltage below the plausible range. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
Is it safe to drive with P2494?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.8–2 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Cooler Bypass Position Sensor B1
Related codes
- P2499EGR Cooler Bypass Position Sensor Circuit Low Bank 2
- P2491EGR Cooler Bypass Control Circuit High Bank 2
- P2492EGR Cooler Bypass Position Sensor Circuit Bank 1
- P2493EGR Cooler Bypass Position Sensor Range or Performance Bank 1
- P2495EGR Cooler Bypass Position Sensor Circuit High Bank 1
- P2496EGR Cooler Bypass Position Sensor Circuit Intermittent or Erratic Bank 1
- P2497EGR Cooler Bypass Position Sensor Circuit Bank 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.