How to Fix ECM Communication Issues in Detroit Series 60

When you’re dealing with a Detroit Series 60 engine and your truck won’t start or communicate with the ECM (Engine Control Module), you’re likely facing a common problem.

Check power supply from the battery

First, check the power supply to your ECM. If your truck isn’t starting or communicating with the ECM, ensure both the 12-volt and ground connections are secure. Bad wiring, faulty batteries, or a blown fuse can disrupt the power needed for the ECM to function.

What to check:

• Battery grounds and voltage: Verify that the 12-volt connections are present and secure.
• Wiring and fuse: Inspect for any bad wiring or blown fuses that could interrupt the power supply.

Here is a diagram that shows the key connections. The letters on the diagram correspond to each pin, with some being battery-positive and others battery-negative.

Verify ignition 12 volts

The next step is to ensure that you’re getting the proper 12-volt signal from the ignition. On the OEM connector, focus on pin B3, where the ignition 12 volts should be supplied. If this voltage is not present, the ECM won’t function correctly.

What to check:

• Pin B3: Ensure that the 12-volt signal is present on pin B3 from your ignition system.

You’ll find the ECM power supply connector just beneath the ignition connection. If you’re experiencing this issue on your Series 60 engine, this could be the culprit preventing your ECM from communicating.

By checking these two areas: power supply and ignition voltage, you can quickly diagnose why your Series 60 engine isn’t communicating with the ECM.