Powertrain, generic (extended)

P2495 EGR Cooler Bypass Position Sensor Circuit High (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2495 covers a bank 1 bypass position signal that climbs close to the reference voltage. On GM Duramax diesels the 2017 calibration fails it above 99 % of 5 V in 200 out of 250 samples, with the same enable conditions as the low test, and rates it Type B. In the field GM saw it on 2015 LML-powered full-size pickups: preliminary bulletin PI1449 lists it with P2493, P24C4 and P06A3 and has the whole bypass valve replaced. That combination is a useful hint: a shared 5 V supply fault (P06A3) can drag several sensors along, so check the reference circuit before condemning parts. Otherwise an open ground wire or a signal wire touching supply is typical. Low voltage is P2494, bank 2 P249A.

Likely causes

Open sensor ground wire
Defective bypass valve with integrated sensor
Fault in the shared 5 V reference circuit
Signal wire touching a voltage source

Symptoms

  • Check engine light after two trips
  • Additional sensor supply codes stored at the same time

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–900
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egr cooler bypass position sensor b1

Related codes

P2492P2493P2494P249AP24C4P06A3

References: gsi.ext.gm.com, static.nhtsa.gov, gsi.ext.gm.com.