Powertrain, generic (extended)

P2C03 Fuel Pressure Regulator D Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2C03 is set when the switched low side of the regulator D control circuit has contact with ground. GM documents it in 23OBDG07 and 24OBDG07 for the second fuel quantity control valve, where it mirrors P0091 of the first valve. With the driver off, a healthy circuit shows a voltage on this line; if it is pulled low, the ECM concludes that less than about 0.5 ohm separates the pin from ground. The check needs more than 10.9 V supply and an engine speed above 80 rpm and counts 20 events before reporting, on the first trip. A short at the supply end of the same driver is a different GM code (P3138), so the code already tells which wire to inspect: typically the low-side lead chafed against the engine or a damaged valve connector.

Likely causes

Low-side wire chafed through to ground
Damaged or wet valve connector
Internal short in the quantity control valve

Symptoms

  • Check engine light on
  • Reduced engine power
  • Rough running at high load

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–900
Time0.5–3 h

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

Parts involved

fuel pressure regulator dhigh pressure fuel pumpwiring harness

Related codes

P2C02P2C04P0091P233B

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