Iveco 1.1 – Engine ECU (EDC MS 6.2): LIGHT CONSTANT Vehicle speed signal

The vehicle speed signal is absent, not plausible, or the circuit (specifically between the speedometer/tachograph and the ECU) is shorted to positive or ground. Symptoms include a steadily illuminated EDC warning light, malfunctioning speedometer, cruise control/PTO failure, and gearbox shifting issues.

• Iveco Daily
• Iveco Eurotrakker
• Iveco Trakker
• Iveco Stralis
• Iveco Eurocargo

1. 1

   Connect an Iveco-approved diagnostic tool to read live parameters and compare the speed read by the ECU with the speedometer indication during a road test.

2. 2

   Locate the vehicle speed sensor on the gearbox, remove it, and check the magnetic tip for metal filings or chips that can disrupt the signal.

3. 3

   Inspect the 4-pin round connector at the sensor for oxidation or water ingress.

4. 4

   Test the wiring harness for continuity, specifically checking for a short to ground or short to positive between the sensor, the instrument cluster (Pin A1), and the EDC control unit (Pin B4).

5. 5

   If equipped with a tachograph, verify that it is powered and functioning, as the speed signal is often routed through the tachograph (B7 connection) before reaching the ECU.

1. 1

   Clean the sensor

   If metal filings are found on the sensor tip during the diagnostic check, clean the sensor, reinstall it, and test drive the vehicle to see if the signal returns.

2. 2

   Repair wiring

   If continuity tests reveal a short or open circuit in the wiring loom between the gearbox, tachograph/speedometer, and the EDC MS 6.2 unit, repair or replace the affected wiring section.

3. 3

   Replace the sensor

   If the wiring is intact, the tachograph is functioning, and the sensor is clean but still not outputting a signal, the vehicle speed sensor has failed internally and must be replaced.

4. 4

   Clear codes

   Reconnect the diagnostic tool, clear the stored EDC fault codes, and perform a road test to ensure the speedometer functions and the EDC light remains off.