Challenger E9070 – ECM or Transmission Controller: Signal Engine Speed Issue

The system has detected a problem with the engine speed signal. This generic fault points to an issue within the system that measures and communicates the rotational speed of the engine to the Engine Control Module (ECM) or transmission controller. The exact nature of the problem is not specified by the code alone, and further diagnosis is required to determine if the fault lies with the sensor, wiring, tone ring, or the control unit itself.

• 35
• 45
• 55
• MT535B
• MT665B
• MT700
• MT765C
• MT800
• MTC835
• MTC845
• MTC855
• MTC865

1. 1

   Inspect the wiring harness leading to the engine speed sensor for damage (fraying, cuts, abrasions, melting) and ensure connectors are clean, free of corrosion, and securely latched (including under-floor connections).

2. 2

   Check fuse blocks for blown fuses related to the ECM or other control modules, and clean the ground stud on the tractor's frame.

3. 3

   Inspect the engine speed sensor for physical damage or metallic debris buildup.

4. 4

   Inspect the tone ring (reluctor wheel) for damaged, bent, or missing teeth.

5. 5

   Test the sensor: For magnetic pickup sensors, measure resistance across terminals (compare to spec; 'OL' indicates a fault). Note that one AGCO Power training document warns against performing a resistance test with a multimeter on certain sensors. For Hall-effect sensors, test for a DC voltage pulse with the ignition on.

1. 1

   Disconnect battery

   Always disconnect the vehicle's battery before working on electrical components for safety.

2. 2

   Locate the engine speed sensor

   Location varies by model: front housing of transmission (35/45), back of engine reading the flywheel (MT665B), or intermediate speed sensor (MT535B).

3. 3

   Remove the sensor

   Unplug the electrical connector, unbolt the sensor from its housing, and be prepared for potential fluid leakage.

4. 4

   Install the new sensor

   Clean the mounting surface, seat and lubricate O-rings, and install the sensor. If adjustable, set the air gap between the sensor and tone ring to manufacturer specifications (often 0.015 to 0.025 inches).

5. 5

   Reconnect and clear codes

   Secure the electrical connector and reconnect the battery. Start the tractor, let it run for a few minutes, shut it off to allow the system to reset, and clear stored codes with a scan tool.