Lost Communication With Fuel Injector Control Module

What it means

The engine computer (ECU) or another module has stopped receiving messages from the fuel injector control module over the CAN bus. On some engines, especially diesels, this module drives the injectors instead of the engine computer, so the engine may not start or may run badly when it is lost. The cause is usually a weak battery, module power, its connector or the bus wiring, and several U codes together point to a bus or power problem.

Related codes: U0100P0201P0087P0562U0001U0106

Symptoms5

• Hard starting or no start.
• Rough running, misfires or loss of power.
• Engine stalling while driving in some cases.
• Check engine light on, sometimes with injector codes.
• Scan tool cannot communicate with the injector module.

Possible causes6

• Weak battery or low voltage while cranking, since this module needs a stable voltage.
• Blown module power fuse or faulty relay.
• Loose or corroded connector from engine heat and vibration.
• Poor module ground.
• Open or shorted bus wiring to the module.
• Internal module failure from heat or repeated low voltage.

How to diagnose6

1. Read codes from all modules; if many modules report lost communication, start with the battery and the bus, and if only the fuel injector control module is missing, focus on it.
2. Try to communicate with the fuel injector control module directly with a scan tool; no response points to lost power, ground or wiring to it.
3. Locate the fuel injector control module from the manufacturer information, which is a separate module on some engines, especially diesels, while on most vehicles it is built into the engine computer, then check its power fuse and measure power and ground at its connector.
4. Inspect the module connector for water, corrosion or loose terminals, and check the bus wiring to it.
5. Disconnect the battery and measure resistance between the CAN bus wires at the module connector, comparing with the manufacturer specification to find an open or short.
6. Load-test the battery and measure voltage while cranking, because a voltage drop is a common cause of this code.

How to fix6

1. Charge or replace the battery, and clean and tighten its terminals.
2. Replace the blown fuse after finding why it blew.
3. Clean the module connector and repair the ground or damaged bus wiring.
4. Update the module software if the manufacturer has an update.
5. Replace the fuel injector control module if proven faulty with good power and bus wiring, then program and code it to the vehicle.
6. Clear codes in all modules and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a battery, fuse or connector, rises with wiring repairs in the engine bay, and is highest if the injector module must be replaced and programmed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions