Troubleshooting FICM Codes

Intended Audience

This guide is intended for technicians who possess a digital multimeter and have basic multimeter skills, including checking for continuity, voltage, and resistance.

• A way to check and clear codes is required.
• If testing for shorts in an injector coil, an LCR meter is required. A cost-effective entry-level option that performs well for this purpose is the Atlas LCR45.
• Technicians should also be able to read basic wiring diagrams and identify wires based on those diagrams.

A connector diagram is available upon request.

Code Combinations That Can Indicate a Possible FICM Issue

LLY Engines:

• P2146 and all of the following: P0201, P0204, P0206, P0207
• P2149 and all of the following: P0202, P0203, P0205, P0208

LB7 Engines:

• P1261 and all of the following: P0201, P0204, P0206, P0207
• P2162 and all of the following: P0202, P0203, P0205, P0208

Testing Steps

1. Use a multimeter to check for a short between the injector supply wire and an injector ground at the FICM connector. On the diagram this is typically labeled Injector Supply Voltage and Fuel Injector X Command.
   • The reading should be open or show very high resistance if no short exists.
2. If no short is found, check resistance between the injector supply line at the FICM and the ground of an injector on the same bank.
   • You should measure low resistance (< 1 Ohm).
   • If resistance is higher or open, a broken wire is likely.

If the problem is intermittent, the multimeter may only show a short when the wire is in a certain position. In that case, we recommend returning the FICM for evaluation to rule it out.

If both P2146 and P2149 are triggered — separately or together — along with their four corresponding injector codes, this is a strong indication of a potential FICM problem.

U0105 (LLY) or U1800 (LB7)

If either of these codes appears along with a no-start condition, a bad FICM is possible — but there are several other potential causes to rule out first.

Diagnostic Steps

1. Check that the EDU/FICM fuse is not blown.
2. With the key on and the fuse inserted, verify power on both sides of the fuse.
3. Confirm that both FICM ground and FICM ignition power are good.
4. Check injector supply voltage (both wires) to ground with the key on.
   • You should see approximately 12 volts.
   • If no voltage is present, the FICM should be sent back for evaluation.

Code Combinations That Typically Do Not Indicate a FICM Failure

LLY Engines:

• P2146 with 1 or 2 of the following: P0201, P0204, P0206, P0207
• P2149 with 1 or 2 of the following: P0202, P0203, P0205, P0208

LB7 Engines:

• P1261 with 1 or 2 of the following: P0201, P0204, P0206, P0207
• P2162 with 1 or 2 of the following: P0202, P0203, P0205, P0208

Testing Notes

It is very difficult to identify a bad injector coil using resistance measurements because the resistance difference between a good and bad coil is extremely small.

An inductance test is a more reliable method — compare the value of an injector that is setting a code with one that is not to determine the fault.

Symptoms That Do Not Indicate a Bad FICM

1. Truck Starts, Runs Briefly (<1 Minute), Then Dies

   This usually indicates air in the fuel line. Follow the manufacturer's procedure for bleeding the air again. It is easier to perform this with one person pumping the primer while another cranks the engine.

2. Loss of Prime After a New FICM Installation (After Sitting for a While)

   This is most often caused by banjo bolts that are not properly tightened or sealed. It can also occur if fuel lines were disturbed during installation, creating a small leak.

   • Inspect for wet fuel around fittings or lines.
   • If no visible fuel leaks are found, slightly tighten the banjo bolts and recheck.