FMI 9 - Data Erroneous - Commanded Fuel Pressure
Fuel pressure sensor is reporting an incorrect pressure value to the engine control module.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The fuel pressure sensor is sending data that doesn't match what's happening in the fuel system. For example, it might say pressure is 10 psi when it really is 50 psi, which confuses the engine control module.
What the computer is actually seeing
The engine control module (ECM) sees fuel pressure readings that are inconsistent with expected values based on engine demand and system operation.
What a healthy reading looks like
Normal fuel pressure is between 45-60 psi depending on the engine type and specific system. Anywhere outside this range can trigger code SPN 2662 if it doesn’t match what the ECM expects.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the fuel pressure with a gauge. It should read between 45-60 psi. If not, go to step 2.
- 22. Inspect the wiring and connectors going to the fuel pressure sensor for damage or corrosion. Repair as needed.
- 33. If wiring is good, replace the fuel pressure sensor with a known good unit and retest.
- 44. If the issue persists, check for fuel system obstructions or pump performance using a multimeter and injector pulse width tests.
Common causes
- Faulty fuel pressure sensor
- Wiring issues (shorts or opens)
- Fuel system contamination
- Faulty fuel pump
- Incorrect fuel pressure regulator operation
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to address this soon as it can affect engine performance and fuel economy.
Will this code come back after clearing?
If the underlying issue isn't resolved, yes, it will come back.
Why does this code pair with others like SPN 2661?
They both relate to fuel system performance and sensor readings, indicating related issues.
Working a real vehicle right now?
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