Detroit DD13 SPN 27 FMI 9 — EGR Valve Position Abnormal Update Rate

Code Details

Plain-English Meaning

The DD13 EGR system electronically controls the EGR valve to recirculate a portion of exhaust gas into the intake manifold, reducing combustion temperatures and NOx emissions. The EGR valve actuator includes a position sensor that reports valve position back to the ECM over the CAN bus at a defined update rate. When the ECM detects that position updates are arriving at an abnormal rate — whether too infrequently, with timing errors, or intermittently dropping out — it logs SPN 27 FMI 9. On the DD13, this fault most commonly results from a connector or wiring issue at the EGR valve actuator rather than a mechanical valve failure. Vibration, temperature cycling, and moisture exposure at the actuator connector can cause intermittent contact that produces abnormal update rate patterns. A failing actuator with degraded internal communication electronics is a less common but possible cause.

SPN 27 is Exhaust Gas Recirculation 1 Valve Position; FMI 9 indicates the ECM is receiving the position data at an abnormal rate that does not match the expected CAN bus transmission frequency for the EGR actuator node. On GHG17 DD13 engines, the EGR valve actuator is an integrated electromechanical assembly that includes the motor, drive, and position sensor in one unit. The actuator communicates over the engine CAN bus, and Detroit DiagnosticLink provides visibility into EGR valve position live data and CAN node communication health. The DiagnosticLink EGR actuator test commands the valve to specific positions and measures the response to determine whether the actuator can follow commands and report accurate position feedback.

Common Symptoms

• Check engine lamp illuminated
• EGR system reduced performance or disabled EGR flow
• Potential NOx-related performance changes if EGR is not operating correctly
• Intermittent fault history that may correlate with engine vibration or temperature extremes

Possible Causes

Possible causes may include the items below. The list is not a parts diagnosis.

• Loose or corroded EGR valve actuator connector causing intermittent CAN signal dropout
• Wiring harness damage between the EGR actuator and the ECM
• CAN bus degradation affecting the EGR actuator communication node
• Failing EGR valve actuator with degraded internal electronics or position sensor
• Mechanical restriction in the EGR valve causing abnormal actuator response timing

First Checks

• Inspect the EGR valve actuator harness connector for corrosion, loose pins, water ingress, or terminal damage and reseat the connector securely
• Check the wiring between the EGR actuator and the ECM for chafing, heat damage, or routing issues near moving components
• Connect DiagnosticLink and monitor live EGR valve position data while wiggling the actuator connector and harness to check for intermittent signal dropout
• Review CAN bus node status in DiagnosticLink to confirm all expected nodes are communicating and there are no other CAN-related fault codes from different systems
• Perform the DiagnosticLink EGR actuator actuation test and confirm the valve moves through its full range and returns accurate position feedback

Can I Keep Driving?

The DD13 is typically driveable with this fault active, but EGR flow may be disabled, affecting emissions compliance. Diagnose and repair promptly to restore EGR system operation.

Related Lookup Pages

• FMI 9 explanation
• Detroit Diesel manufacturer hub
• Search this code