Case IH P67 – Engine Control Unit (ECU) / Fuel Pump Control Module (PCU): IAT System, Data Valid But Above Normal Range

The Engine Control Module detects a failure in the static or dynamic plausibility of the internal pump speed (Increment Angle Time sensor). This can be a static failure where the system does not recognize a whole number of increments per segment, or a dynamic failure where the difference between the crankshaft speed sensor and the pump's internal IAT sensor is outside limits.

• MXM
• MXM 120
• MXM 130
• MXM 140
• MXM 155
• MXM 175
• MXM 190
• TM120
• TM130
• TM140
• TM155
• TM175
• TM190

1. 1

   Check for active crankshaft speed sensor codes, as a failing crank sensor can trigger this IAT plausibility code

2. 2

   Inspect the wiring harness and connectors between the Engine Control Module and the fuel injection pump for corroded, pushed-back, or loose pins

3. 3

   Verify the mechanical timing of the fuel injection pump drive gear to ensure it hasn't slipped out of sync with the crankshaft

1. 1

   Diagnose Primary Sensors

   If a crankshaft speed sensor code is present alongside T67/3616, replace the crankshaft speed sensor first, clear the codes, and test the system.

2. 2

   Test Harness Continuity

   Disconnect the main harness at the fuel injection pump. Use a multimeter to measure resistance and ensure continuity back to the ECM. If resistance is high (above 3-4 ohms) or indicates an open circuit, repair the wiring harness.

3. 3

   Check Pump Timing

   Pin the engine at Top Dead Center (TDC) and attempt to insert the injection pump timing pin tool (Tool No. 380000404) into the pump hub. If the pin does not engage the timing plate, the mechanical timing is incorrect and must be reset.

4. 4

   Replace the Injection Pump

   If the wiring is intact, the crankshaft sensor is functioning, and the mechanical timing is correct, the internal IAT (cam speed) sensor has failed. Because this sensor is integrated into the pump's internal control module, the entire fuel injection pump must be removed and replaced (or sent to a specialized diesel injection shop for remanufacturing).

5. 5

   Reassembly and Calibration

   Install the new injection pump, bleed the fuel system, clear the error codes using the diagnostic service tool, and run the engine to verify the repair.