Case IH 3256 – ECU A-095: ECU internal failure - NTP error in ADC monitoring

This code indicates an internal failure within the Electronic Control Unit (ECU) regarding its Analog to Digital Converter (ADC). The ECU uses a No-load Test Pulse (NTP) operation to check the efficiency of the ADC. A fixed test input voltage is sent to and converted by the ADC, which must read between 4.73 and 4.83 Volts. If the error counter exceeds 15 times, fault code 3256 (DTC E21D) is logged.

• Farmall
• Steiger T4B
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Puma Series Tractors

1. 1

   Verify that the machine's battery power supply has not been connected to an external power supply (such as a jump box or external charger). Disconnect if present and test for normal operation.

2. 2

   Inspect for a faulty charging system (alternator overcharging or undercharging).

3. 3

   Check for a faulty solenoid or a faulty wire harness that could be causing voltage spikes or shorts to the ECU.

1. 1

   Software Verification

   Connect the diagnostic service tool and check the ECU A-095 for the appropriate software version.

2. 2

   Re-flash ECU

   If the software is outdated or corrupted, re-flash the ECU A-095 with the latest software.

3. 3

   Clear and Retest

   Clear the fault codes and operate the machine to see if the NTP error returns.

4. 4

   Component Replacement

   If the fault persists after verifying the wiring, charging system, and re-flashing the software, the internal ADC is permanently failed. The ECU A-095 must be replaced.