Bendix EC-60 UDS 49 / SPN 801 FMI 2 — Retarder Relay Open Circuit or Shorted to Ground

Code Details

Plain-English Meaning

The EC-60 detected a open circuit in the retarder relay circuit. The EC-60 commands this relay to suppress the retarder (engine brake, exhaust brake, or hydraulic retarder) during ABS activation — applying the retarder while ABS is active can cause wheel lockup. A fault here means the EC-60 may not be able to suppress the retarder during an ABS stop.

The Bendix EC-60 table maps UDS code 49, blink code 12-04, J1587 013-02, and J1939 SPN 801 FMI 2 to this ABS/ATC/ESP diagnostic entry. The Bendix source indicates an ABS and/or ATC/ESP warning lamp can be on for this entry. The EC-60 continuously monitors wheel speed sensor circuits, pressure modulation valve output drivers, supply voltage quality, J1939 network data from the engine and transmission controllers, and internal self-diagnostic routines. When any monitored value falls outside its acceptable range — or a circuit does not respond as the module expects — the EC-60 logs a diagnostic trouble code and may disable the affected ABS, ATC, or ESP function. Bendix ACOM Pro or a compatible diagnostic interface is the required tool for reading live sensor data, running actuator tests, performing calibrations, clearing latched codes, and adjusting EC-60 configuration parameters. Generic J1939 scan tools can read the SPN/FMI but cannot access EC-60-specific live data screens or configuration settings.

Common Symptoms

• ABS lamp on
• Retarder may remain active during ABS events, potentially worsening wheel lockup
• Normal ABS activation still occurs but without retarder suppression
• Fault may only be noted during a diagnostic scan, not apparent during regular driving
• Scan tool shows Bendix EC-60 UDS 49 / SPN 801 FMI 2

Possible Causes

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

• Relay coil open, relay not seated, or broken wire to relay socket
• Relay failed internally (open coil, contact failure)
• Relay not fully seated in its socket
• Corrosion on relay socket contacts
• Harness damage at the relay connector

First Checks

• Locate the retarder relay and confirm it is fully seated in its socket.
• Measure relay coil resistance (typically 70–90 Ω for a standard automotive relay).
• Check relay socket contacts for corrosion and confirm power and ground are present at the socket with ignition on.
• Measure continuity from EC-60 relay output pin to relay coil pin.
• After repair, clear with Bendix ACOM and verify on a test drive that no return code appears.

Can I Keep Driving?

A retarder relay fault means the EC-60 may be unable to suppress the retarder during an ABS-active braking event. If the engine brake, exhaust brake, or hydraulic retarder remains engaged during a wheel lockup, it can fight ABS modulation and extend stopping distance. This is a safety-relevant condition — operate without the retarder enabled until the fault is resolved if possible, especially on slippery surfaces.

Related Lookup Pages

• FMI 2 explanation
• Bendix manufacturer hub
• ABS / ATC / ESP fault codes
• ABS Light symptom page
• Brake Warning Light symptom page
• Search this code