P0611: Fuel Injector Control Module Performance

P0611 concerns systems with a separate injector control module or injector driver stage. On GM's 6.6 L Duramax LB7/LLY the injector driver unit reports a microcontroller, monitoring or converter fault or a timeout to the engine module over CAN; the code sets after 30 of 50 checks at 125 ms with battery voltage of 10–18 V, and the lamp follows after two trips. On Ford's 6.0 L Power Stroke the injector module steps battery voltage up to about 48 V; Ford's bulletin requires it to stay above 45 V during the last 10 s of the injector prime, with the battery at 11.5 V or more – weak batteries strain and damage the converter. Newer Ford diesels check an internal reference measurement (0–3300 mV, 5 s). Results are hard or no starting, rough running and low power.

Symptoms

• Hard or no start, especially when cold
• Rough running, misfires
• Lack of power
• Check engine light (GM after two trips)

Most likely causes

• Faulty voltage converter or driver stage in the injector module (Ford 6.0 L)
• Low battery voltage, weak batteries or poor ground
• CAN or supply line between engine and injector module disturbed
• Faulty module software (update available)

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the connector and wiring of the injector indicated
2. Compare the reading with other engine data while varying the engine speed.
3. Measure the resistance and compare it with the manufacturer's specification
4. Check the control signal with an oscilloscope; on direct injection or diesel engines, leave this to a repair shop because of the high voltages
5. On diesels, check the per-cylinder injection corrections

Good to know

• Repair difficulty: hard
• It can trigger limp mode.
• It affects emissions.

What each character of P0611 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 6: Control modules and outputs
• 11: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0611?

Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

What causes code P0611?

The most common causes are: faulty voltage converter or driver stage in the injector module (Ford 6.0 L); low battery voltage, weak batteries or poor ground; cAN or supply line between engine and injector module disturbed.

Related codes

• P0612Fuel Injector Control Module Relay Control
• P062BInternal Control Module Fuel Injector Control Performance
• P0201Cylinder 1 Injector A Circuit/Open
• P0606Control Module Processor
• P0562System Voltage Low

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 2004file9
• gsi.ext.gm.com: 2005file9
• fordservicecontent.com: tsb10 12 06

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.