Case IH 19665 – Engine Control Module (ECM): Intake manifold pressure is too low

This code indicates that the measured boost/intake manifold pressure is lower than the expected value for the current engine operating conditions. The engine is not receiving the required amount of pressurized air from the turbocharger, which can lead to a loss of power, poor fuel efficiency, and increased emissions.

• Tier 4b
• Magnum 215
• Magnum 245
• Magnum 255
• Magnum 275
• Magnum 305
• Magnum 340
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 140
• Puma 165
• Steiger
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Axial-Flow 7250
• Axial-Flow 8250
• Axial-Flow 9250
• 580N
• 590SN
• SV340B
• TV450B
• G-Series Wheel Loaders

1. 1

   Inspect the Intake System: Check for physical air leaks between the turbocharger and the intake manifold. Look for cracked charge-air hoses, loose hose clamps, or a damaged charge air cooler (intercooler).

2. 2

   Check Sensor Wiring: Inspect the 4-pin electrical connector at the Intake Manifold Pressure Sensor. Look for corrosion, pushed-out pins, or frayed wires. A short to ground or an open circuit in this harness will cause the ECM to read a falsely low pressure.

3. 3

   Inspect the Turbocharger: Verify that the turbocharger wastegate is not stuck open and that the compressor wheel is intact.

4. 4

   Check the Air Filter: Ensure the primary and secondary air filters are not severely restricted, which can starve the turbocharger of air.

1. 1

   Preparation

   Turn off the engine, remove the key, and allow the engine to cool.

2. 2

   Locate the Sensor

   Locate the Intake Manifold Air Pressure and Temperature Sensor. It is mounted directly on the intake manifold, downstream of the turbocharger and charge air cooler.

3. 3

   Disconnect Wiring

   Carefully depress the locking tab on the 4-pin electrical connector and pull it away from the sensor.

4. 4

   Remove the Sensor

   Remove the retaining bolt securing the sensor to the manifold. Gently twist and pull the sensor straight out of the mounting hole.

5. 5

   Install the New Sensor

   Lubricate the O-ring on the new sensor with a small drop of clean engine oil to prevent tearing. Push the sensor into the manifold port until it is fully seated.

6. 6

   Secure and Reconnect

   Reinstall and tighten the retaining bolt. Plug the 4-pin electrical connector back in until it clicks securely.

7. 7

   Clear Codes

   Use a diagnostic service tool (like the CNH EST) to clear the 19665 fault code. Start the engine and check for any air leaks around the new sensor base.