Deutz-Fahr 102 – EMR3: Cable break or short circuit

The engine control unit (EMR3) has detected an electrical anomaly, such as a cable break or short circuit, in the charge air pressure sensor (MAP/boost pressure sensor) circuit. This sensor measures intake manifold air pressure after the turbocharger to optimize fuel injection. A failure in this circuit can correspond to FMI 2 (data erratic), FMI 3 (voltage above normal/short to high), or FMI 4 (voltage below normal/short to low). When active, the dashboard error lamp will typically show a permanent light, leading to a loss of engine power, excessive black smoke, and incorrect turbocharger operation.

• TCD 2012
• TCD 2013
• TCD 2015
• TCD 3.6
• TCD 2.9
• TCD 4.1

1. 1

   Visually inspect the wiring harness leading to the charge air pressure sensor for chafing, cuts, melting, or corrosion, especially near securing brackets

2. 2

   Disconnect and inspect the electrical connector at the sensor for corrosion, moisture, damage, and ensure it locks securely

3. 3

   Check for multiple active fault codes, which may indicate a broader issue with shared power supply or ground wires in the engine harness

4. 4

   For FMI 3 or 4: Measure the reference voltage between the 5V supply pin and ground pin at the harness connector with the ignition on and sensor disconnected (should be 4.75 - 5.25 volts)

5. 5

   For FMI 4: Check for shorts to ground by measuring resistance between the signal wire pin and chassis ground with the ignition off and sensor disconnected (should be an open circuit/very high resistance)

6. 6

   For FMI 3: Check for shorts to power by testing continuity between the signal wire and the 5V supply or other power sources with the ignition off and sensor disconnected (should be no continuity)

7. 7

   Verify continuity of the signal, supply, and ground wires between the sensor connector and the ECU connector to rule out a wire break

1. 1

   Perform Diagnostic Checks

   Complete all the diagnostic checks listed above to isolate the root cause of the fault.

2. 2

   Repair Wiring

   If a wiring issue is found (break, short, or corrosion), repair or replace the damaged section of the harness. Ensure all connections are clean and secure.

3. 3

   Replace the Sensor

   If the wiring and connectors are confirmed to be in good condition, the charge air pressure sensor itself is likely faulty. Replace the sensor with a new part.

4. 4

   Clear Fault Codes

   After the repair, use a diagnostic tool to clear the fault codes from the ECU's memory.

5. 5

   Verify the Repair

   Start the engine and let it run for a few minutes. Re-check for any active fault codes to confirm that the repair was successful. With the ignition on and the engine off, the charge air pressure reading should be consistent with the atmospheric pressure.