Powertrain, generic (extended)

P233E Fuel Pressure Regulator B Solenoid Supply Voltage Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P233E concerns the feed side of fuel pressure regulator B: the line from the ECM's high-side driver to the solenoid is shorted to ground. GM documents it for its 2025 diesels (table 25OBDG04A); there, regulator B means the rail pressure regulator valve. The ECM looks at the voltage across the high-side driver while it is switched on; if that voltage is high, the output is being pulled down, as through an impedance to ground under roughly half an ohm. 61 failures within 122 samples of 6.25 ms, enabled above 11 V and outside cranking, set the code as Type A, MIL in the first trip. The driver normally shuts off to protect itself, so the valve stops working and rail pressure can no longer be held. Ground-side faults use P2294 to P2296; P233F is the short to power.

Likely causes

Supply wire to the regulator rubbed through to ground
Regulator solenoid shorted internally or to its housing
Water or corrosion in the regulator connector
High-side driver in the engine control module damaged

Symptoms

  • Check engine light on in the first trip
  • Reduced power, rail pressure deviation
  • Hard starting or stalling possible

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–700
Time0.5–2.5 h

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

Parts involved

fuel pressure regulator bengine control modulewiring harness

Related codes

P233DP233FP2295P2293P00C9

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