Case IH 19362 (F-158-18) - ECU – DCU (Dosing Control Unit) or ECM (Engine Control Module): Battery voltage is too low to allow proper diagnosis of output powerstages

The voltage supplied to the module is too low for the system to perform its internal diagnostic checks on the output power stages.

• VESTRUM CVX
• Case IH Magnum Series 235 - 340 (Series 4)
• Case IH Steiger Series 350 - 600 HP
• Case IH Farmall Series 40, 45, 50 (with CVT), and 115U

1. 1

   Perform a battery load test to ensure main equipment batteries hold a proper charge and provide correct base voltage (12V or 24V).

2. 2

   Probe the power supply pins at the DCU wiring harness connector to verify the voltage reaching the module.

3. 3

   Inspect the wiring harness and grounds between the battery/alternator and the DCU for chafed wires, loose ground straps, or corrosion.

4. 4

   Test alternator output to verify it is charging the system correctly when the engine is running.

1. 1

   Disconnect power

   Turn the battery disconnect switch to the OFF position. Wait at least 10 minutes after turning the key off before disconnecting the battery so the DCU can complete its purge cycle and save data.

2. 2

   Clean and repair connections

   If diagnostic checks revealed corrosion or a loose connection at the DCU harness or battery terminals, clean the contacts with electrical contact cleaner, replace damaged pins, and securely tighten all grounds.

3. 3

   Replace batteries

   If the batteries failed the load test (low base voltage cause), replace them with new heavy-duty equipment batteries and clear the fault codes.

4. 4

   Replace the DCU

   If the harness provides perfect voltage to the DCU but the code persists, the DCU's internal power evaluation circuit has failed. Remove DEF lines and electrical connectors, unbolt the DCU, and install the new unit. Note: A new DCU requires software installation and calibration using the CNH Electronic Service Tool (EST).