Powertrain, generic · Fuel and air metering, auxiliary emission controls
P00C9 Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit Low
Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible
Some engine control modules switch the solenoid of fuel pressure regulator A on both sides: the ground side is monitored by P0090 to P0092, the supply side (high-side driver) by P00C8 to P00CA. On gasoline direct injection the regulator is typically the control valve on the high-pressure pump; on some diesels it is the regulator designated as regulator 1. P00C9 reports a short to ground on the supply side. Rail pressure can then not be controlled, causing starting problems, stalling or reduced power; documented systems turn on the warning light in the first drive cycle.
Likely causes
Supply wire to the solenoid chafed and shorted to ground
Solenoid coil shorted
Water or corrosion in the connector
High-side driver in the engine control module faulty
Symptoms
- Check engine light on
- Hard starting or stalling
- Loss of power or limp mode
Repair estimate
DifficultyMediumDIY possible
Parts and labour€50–2,000
Time0.5–3 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
fuel pressure regulatorfuel pressure regulator wiringhigh pressure fuel pumpengine control module
Related codes
References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.