Case IH 19572 – Engine Control Module (ECM) / Vehicle Control Module (VCM): SRC Max error for the NOx signal

The signal voltage or data value returning from the Nitrogen Oxide (NOx) sensor has exceeded the maximum allowable threshold programmed into the control module. This condition typically points to a sensor that is shorted to power, an internal failure within the sensor's integrated module, or a severe anomaly in the exhaust gas composition.

• Tier 4b
• Magnum series (180, 200, 220, 240, 250, 280, 310, 340)
• Puma series (150, 165, CVT models)
• Maxxum series
• Farmall series (110A, 120A, 130A, 140A)
• Combines (5140, 6140, 7140, 7240, 8240, 9240)
• Patriot Sprayers (2250, 3240, 3340, 4440)
• Titan Floaters (3040, 3540, 4040, 4540)
• Case N-Series Tractor Loader Backhoes (TLBs)
• Farmlift Telehandlers

1. 1

   Inspect the NOx sensor wiring harness and connectors for chafing, melting, or corrosion (a common cause of short to power errors due to extreme exhaust heat).

2. 2

   Use a multimeter to verify the power supply, ground, and CAN communication lines at the NOx sensor connector. Ensure there is no short circuit to a voltage source on the signal line.

3. 3

   Check for exhaust leaks upstream of the NOx sensor, which can skew readings.

4. 4

   Ensure the Diesel Exhaust Fluid (DEF) system is dosing correctly and that the DEF quality is good, as poor emissions reduction can cause the sensor to read out of bounds.

1. 1

   Turn off machine and disconnect battery

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the affected NOx sensor

   Locate the affected NOx sensor on the exhaust system (typically mounted downstream of the SCR catalyst).

3. 3

   Disconnect electrical connector

   Disconnect the electrical connector from the NOx sensor module.

4. 4

   Remove the sensor

   Apply penetrating oil to the sensor threads in the exhaust pipe and carefully remove the sensor using a specialized NOx/O2 sensor socket to avoid stripping the threads.

5. 5

   Apply anti-seize compound

   Apply a high-temperature anti-seize compound to the threads of the new NOx sensor (if not already pre-applied by the manufacturer).

6. 6

   Install the new NOx sensor

   Install the new NOx sensor into the exhaust pipe and torque to OEM specifications.

7. 7

   Mount control module and reconnect harness

   Mount the sensor's control module securely and reconnect the electrical harness, ensuring the wiring is routed away from direct heat sources.

8. 8

   Reconnect battery

   Reconnect the battery.

9. 9

   Clear fault code and reset values

   Connect a diagnostic scan tool to clear the 19572 fault code and reset any learned NOx offset values in the ECM.

10. 10

    Run warm-up cycle

    Run the engine through a warm-up cycle to verify the code does not return and that the NOx sensor is reading within normal parameters.