Powertrain, generic · Auxiliary emission controls

P0403 EGR A Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. P0403 concerns the electrical drive of the EGR valve – solenoid, stepper motor, DC motor or vacuum regulator. The module checks the output and sets the code for an open circuit (GM: above 200 kΩ, MIL after two trips; Ford after 4 s, MIL after two trips). Newer systems report shorts separately as P0489 (low) and P0490 (high); Ford and older GM systems include them in P0403. EGR is then switched off for the rest of the trip.

Likely causes

Connector at the EGR valve corroded or loose
Broken control or supply wire
Coil or motor in the EGR valve burnt out
Driver in the engine module

Symptoms

  • Check engine light on
  • EGR switched off: pinging (petrol) or higher NOx
  • Usually no loss of power

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–600
Time0.5–2.5 h

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

What to check first

  1. Inspect connector
  2. Measure solenoid resistance
  3. Check control signal

Parts involved

egr valveegr valve actuatoregr wiringengine control module

Related codes

P0404P0489P0490P0405P0406

References: gsi.ext.gm.com, newtonnet.co.uk, saabwisonline.com, gsi.ext.gm.com.