Case IH 19339 – Engine Control Module (ECM): Timeout Error of CAN-RECEIVE-Frame GPM23

The Engine Control Module (ECM) has failed to receive the "GPM23" (General Purpose Message #2/3) over the CAN bus network within the expected timeframe. The GPM23 message contains the high and low idle engine speed setpoints and is broadcasted by the Body Computer (BC) or Cab Controller.

• Tier 4b
• Case IH T7 Series
• T7.175
• T7.190
• T7.210
• T7.225
• T7.260

1. 1

   Verify the voltage supply to the Body Computer to rule out an under-voltage condition causing the CAN controller to stop broadcasting.

2. 2

   Inspect the CAN cable connecting the Body Computer to the network for disconnected plugs, broken wires, or short circuits.

3. 3

   Use the CNH Electronic Service Tool (EST) to verify the CAN configuration of the Body Computer to ensure it is programmed to broadcast the GPM23 message.

4. 4

   Verify the presence and correct connection of the Body Computer on the network using the diagnostic tool to see if it is communicating on other CAN frames.

1. 1

   Disconnect Battery

   Always disconnect the machine's batteries before testing CAN bus resistance or unplugging modules.

2. 2

   Measure CAN Resistance

   Probe the CAN bus at the diagnostic connector. A healthy CAN bus should read approximately 60 ohms. If it reads 120 ohms, one of the terminating resistors or a segment of the wiring harness is broken. If it reads near 0 ohms, there is a short circuit.

3. 3

   Perform Visual Inspection

   Inspect the wiring harness routing from the cab (Body Computer) to the engine bay (ECM). Look for chafing, pinched wires, or moisture intrusion at the connectors.

4. 4

   Pinpoint Test

   Disconnect the harness at the Body Computer and the ECM. Perform a continuity test on the CAN High and CAN Low wires end-to-end. Test for shorts to ground and shorts to power.

5. 5

   Repair Wiring

   If a broken wire or short is found, repair the CAN bus wiring harness or replace the damaged harness section.

6. 6

   Replace/Reprogram Body Computer

   If the wiring is 100% intact, the terminating resistors are good, and the Body Computer has proper power/ground but is still failing to broadcast the GPM23 message, the Body Computer's internal CAN controller is defective. Replace the Body Computer and flash it with the correct vehicle configuration using CNH EST.