Case IH 12659 – Safety Controller: Pressure sensor cross check - ADC values implausible

The Analog-to-Digital Converter (ADC) values coming from redundant pressure sensors do not match or fall outside the expected operational range. The controller performs a cross check between multiple pressure sensors for safety monitoring; if the voltage or ADC readings contradict each other, the system flags the values as implausible.

• Puma
• Optum
• Magnum
• T7.245
• T7.260
• T7.270

1. 1

   Monitor live ADC voltage values for the brake/system pressure sensors using an OEM diagnostic tool to identify which sensor is reading out of range or dropping out.

2. 2

   Inspect the wiring harness and connectors between the pressure sensors and the Safety Controller for corrosion, moisture ingress, or chafed wires.

3. 3

   Verify that the sensors are receiving the correct 5V reference voltage and have a solid ground to rule out a floating ground.

4. 4

   Ensure there is no mechanical pressure imbalance or blockage in the valve block causing legitimately different pressure readings.

1. 1

   Disconnect power

   Disconnect the tractor battery to prevent electrical spikes during component replacement.

2. 2

   Access the valve block

   Locate the ABS or Trailer brake valve block where the primary and secondary pressure sensors are mounted.

3. 3

   Clean connections

   Disconnect the sensor harnesses and clean the pins with electrical contact cleaner.

4. 4

   Replace pressure sensor(s)

   If wiring tests fine but ADC values remain implausible, replace the faulty pressure sensor(s) identified during live data monitoring. Replacing in pairs is recommended for redundant sensors.

5. 5

   Replace Safety Controller

   If sensors and wiring are perfect, the Safety Controller internal ADC may have failed. Replace the Safety Controller as a last resort.

6. 6

   Relearn and clear codes

   Reconnect the battery, clear the fault codes using the diagnostic tool, and perform a functional brake and pressure test to ensure the cross-check passes.