Case IH 19702 – Engine Control Unit (ECU): Set value of PCV not in plausibility range

The Engine Control Unit (ECU) detects that the commanded set value (PWM signal) sent to the Pressure Control Valve (PCV) does not match expected operational parameters, or the resulting fuel rail pressure does not align with the commanded valve position.

• Tier 4b
• Puma
• Magnum
• Optum
• Steiger
• Axial-Flow
• T7
• T8
• T9

1. 1

   Inspect the electrical connector and wiring harness leading to the PCV for corrosion, chafing, or loose pins (diagnosing a voltage drop or short circuit cause)

2. 2

   Verify low-pressure fuel supply from the lift pump and check for clogged fuel filters (diagnosing a fuel starvation cause)

3. 3

   Check the Fuel Rail Pressure Sensor for inaccurate pressure data (diagnosing a false pressure reading cause)

4. 4

   Perform a leak down test for high-pressure fuel leaks at the rail, injector lines, or excessive injector return flow (diagnosing an inability to build commanded pressure)

5. 5

   Test PCV electrical internal resistance (ohms) against OEM specs and verify the ECU PWM signal using an oscilloscope (diagnosing a failed PCV coil)

1. 1

   Depressurize the System

   Turn off the machine and allow the engine to cool completely. Wait for the system to naturally depressurize before opening any lines.

2. 2

   Clean the Area

   Thoroughly clean the area around the high-pressure pump and the PCV with brake cleaner to prevent dirt from entering the high-pressure fuel system.

3. 3

   Disconnect

   Unplug the electrical harness connector from the PCV.

4. 4

   Remove the Valve

   Unscrew the mounting bolts (or unthread the valve, depending on the specific FPT engine design) and carefully pull the PCV out of its housing.

5. 5

   Prepare the New Valve

   Lubricate the O-rings on the new PCV with clean diesel fuel. Do not use grease or silicone.

6. 6

   Install

   Insert the new PCV into the housing and torque the fasteners to the exact OEM specification (over-tightening can distort the valve internals).

7. 7

   Reconnect

   Plug the electrical harness back in.

8. 8

   Prime the System

   Turn the key to the ON position to allow the low-pressure electric lift pump to prime the system and purge air.

9. 9

   Clear Codes

   Connect the Case IH Electronic Service Tool (EST) to clear the 19702 fault code. Start the engine and monitor the commanded vs. actual rail pressure to verify the repair.