Powertrain, generic (extended)

P245C EGR Cooler Bypass Control Circuit Low (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P245C reports that the control line of the bank 1 bypass actuator is pulled toward ground. GM documents this in its diesel tables: in 2014 the driver stage detects low voltage while it is switched off and treats it as a ground short, and in the 2017 tables the vacuum-switched bypass fails when the resistance to ground drops below 0.5 Ohm in 24 of 30 samples, rated Type B. With the line shorted the actuator may sit permanently in one position, so the cooler is either always bypassed or always used, which the efficiency check P2457 can then also notice. Typical findings are insulation rubbed through against the engine or exhaust, a pinched harness after repairs or a shorted solenoid winding. The open case is P245A, a short to supply P245D, and bank 2 has P2490.

Likely causes

Control wire chafed through and touching ground
Shorted actuator or solenoid winding
Water or corrosion bridging connector pins

Symptoms

  • Malfunction indicator lamp on
  • Bypass stuck in one position, possibly with EGR cooler efficiency code

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–600
Time0.5–3 h

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

Parts involved

egr cooler bypass valve b1

Related codes

P245AP245BP245DP2490P2457

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.