Case IH 19558 – Engine Control Module (ECM / EDC) or Aftertreatment Control Module (ACM): SRC Max error for the binary lambda signal

The voltage signal coming from the binary lambda sensor (which is integrated into the NOx sensor assembly) is exceeding the maximum allowable threshold. This is typically caused by an open circuit, a short circuit to battery voltage (+B) in the sensor's wiring harness, or an internal failure of the NOx sensor itself.

• Tier 4b
• Magnum (180, 200, 220, 240, 250, 280, 310, 340, 380)
• Puma (150, 165, 185, 200, 220)
• Maxxum (115, 125, 135, 145, 150)
• Farmall (110A, 120A, 130A, 140A)
• Steiger series
• Combines 5140, 6140, 7140, 7240, 8240, 9240
• Patriot (2250, 3240, 3340, 4440)
• Titan (3040, 3540, 4040, 4540)

1. 1

   Inspect the wiring harness leading to the upstream NOx sensor (Bank 1, Sensor 1) for chafing, melting from exhaust heat, or physical damage

2. 2

   Disconnect the NOx sensor module connector and check for water intrusion, bent pins, or corrosion

3. 3

   Test the signal wire between the NOx sensor connector and the ECM/ACM for continuity

4. 4

   Check for a short to battery voltage (+B) on the signal wire, which triggers the 'SRC Max' condition

5. 5

   Verify that the sensor is receiving proper power and ground from the module

6. 6

   Ensure there are no other CAN timeout codes present, as the NOx sensor communicates via the CAN network

1. 1

   Preparation

   Turn off the machine, remove the key, and disconnect the negative battery terminal. Allow the exhaust system to cool completely.

2. 2

   Locate the Sensor

   Locate the faulty NOx sensor on the exhaust aftertreatment system (usually the upstream sensor before the SCR catalyst for this specific code).

3. 3

   Disconnect

   Unplug the electrical connector from the NOx sensor control module. Unbolt the module from its mounting bracket.

4. 4

   Removal

   Using a specialized NOx/O2 sensor socket (usually 22mm), carefully unscrew the sensor probe from the exhaust pipe. Note: If the sensor is seized, apply penetrating oil and allow it to soak to prevent stripping the exhaust bung threads.

5. 5

   Installation

   Apply a small amount of anti-seize compound to the threads of the new sensor (if not pre-applied by the factory). Thread the new sensor into the exhaust pipe by hand to prevent cross-threading, then tighten to the OEM torque specification.

6. 6

   Reassembly

   Mount the new NOx sensor control module to the bracket and reconnect the electrical harness.

7. 7

   Clear Codes

   Reconnect the battery. Connect a diagnostic scan tool (such as Case IH EST) to clear the 19558 / P2200 fault code.

8. 8

   Validation

   Start the engine and allow it to reach operating temperature to ensure the code does not return and the inducement/derate mode is deactivated.