SPN 5585 FMI 13: Meaning and Fix
This fault indicates the Engine Fuel 1 Injector Metering Rail 1 pressure during cranking is outside the ECM’s calibrated tolerance range. Typically triggered after ECM replacement or software update without proper rail pressure sensor recalibration. Technicians often see this after a forced DPF regeneration when the rail pressure sensor drifts, causing the ECM to detect a calibration mismatch during the initial cranking phase.
Common Symptoms
- Extended cranking: Engine cranks longer than normal before starting due to inaccurate fuel rail pressure feedback.
- Hard cold start: Cold starts become difficult as the ECM cannot validate rail pressure against its calibration table.
- Intermittent no-start: Engine occasionally fails to start when rail pressure sensor offset exceeds calibration limits.
- Rough idle after start: Post-cranking idle is unstable because the ECM applies incorrect fuel trim based on faulty calibration.
Probable Causes
- Sensor drift: Fuel rail pressure sensor output has drifted outside the ECM’s stored calibration curve over time.
- ECM calibration error: ECM replaced or flashed with incorrect calibration data for the specific fuel metering system.
- Wiring harness damage: Chafed or corroded wires in the rail pressure sensor circuit cause intermittent signal offset.
- Metering rail leak: Internal leakage in the injector metering rail reduces cranking pressure below calibration threshold.
Advanced Technical Analysis
The ECM monitors the fuel rail pressure sensor voltage during cranking and compares it to a stored calibration table. If the sensor output at 0 bar (atmospheric) deviates by more than ±0.5% of the 5V reference, the ECM sets SPN 5585 FMI 13. This is a signal validation check performed before the injection enable logic is activated.
Electrical analysis reveals the sensor signal line has a debouncing timer of 500 ms. A transient offset caused by a poor ground reference or high resistance in the sensor return line can trigger this fault intermittently. MAN factory manuals specify checking the sensor ground pin for voltage drop above 50 mV during cranking.
When this fault is active, the ECM enters a safety fallback that disables the fuel metering rail control and limits engine torque to 30% of rated power. The ECM does not allow full injection until the calibration mismatch is resolved. This prevents potential over-pressurization of the rail.
Long-term diagnostic strategy includes performing a sensor recalibration using manufacturer-specific software like Bosch ESI[tronic] or MAN CATS. Real-world workshops report that after replacing the ECM on a Deutz TCD 2015, failure to run the ‘Rail Pressure Sensor Learn’ routine causes this fault on the next key cycle. Always verify the ECM part number matches the engine variant.
Step-by-Step Troubleshooting Guide
- Read freeze frame: Capture cranking pressure data from freeze frame to compare against sensor calibration at key-on.
- Check sensor supply: Measure 5V reference and ground at rail pressure sensor connector with engine off and key on.
- Perform sensor recalibration: Use OEM diagnostic tool to execute rail pressure sensor zero-point calibration routine.
- Inspect metering rail: Leak test the injector metering rail using a pressure decay test at cranking speed.