Diagnostic Test

CHECK FOR CHARGING SYSTEM DIAGNOSTIC TROUBLE CODES (DTCs)
1. With the scan tool, read Powertrain Control Module (PCM) DTCs.
  Are any Charging System DTCs set?
  
  Yes
  - Repair Charging System DTCs. Refer to DTC INDEX .
  - Perform the ESM VERIFICATION TEST. Refer to ELECTRONIC SHIFT MODULE (ESM) VERIFICATION TEST .
  No
  - Go To 2
CHECK IF VEHICLE WAS JUMP STARTED WITH 24-VOLT SYSTEM
NOTE:
Some Recreational Vehicles (RVs), Buses, and Semi Tractors use 24-volt systems.
1. Ask the customer if the vehicle was jump started by a vehicle with a 24-volt charging system.
  Was the vehicle jump started by a vehicle with a 24-volt charging system?
  
  Yes
  - This is the cause of the DTC. Erase the DTC and return the vehicle to the customer.
  - Perform the ESM VERIFICATION TEST. Refer to ELECTRONIC SHIFT MODULE (ESM) VERIFICATION TEST .
  No
  - Go To 3
CHECK INDICATED ESM SHIFT KNOB BATTERY VOLTAGE
1. Start the Engine and raise the engine speed to 2, 000 rpm.
2. With the scan tool, monitor the ESM Shift Knob Battery Voltage for 60 seconds.
  Does the ESM Shift Knob Battery Voltage read above 18.3 volts at any time during the test?
  
  Yes
  - Go To 4
  No
  - Go To 5
COMPARE ESM SHIFT KNOB VOLTAGE TO BATTERY VOLTAGE
1. Raise the engine speed to 2, 000 rpm.
2. With the scan tool, read the ESM Shift Knob Battery Voltage.
3. Measure the voltage at the Battery.
4. Compare the readings.
  Does the measured voltage reading match the scan tool ESM Shift Knob Battery Voltage reading?
  
  Yes
  - Repair the Charging System for an over charging condition in accordance with the Service Information.
  - Perform the ESM VERIFICATION TEST. Refer to ELECTRONIC SHIFT MODULE (ESM) VERIFICATION TEST .
  No
  - Using the schematics as a guide, check the Electronic Shift Module (ESM) connector and all related in-line connector terminals for corrosion, damage, or pushed out terminals. Pay particular attention to the power and ground circuits. If no problems are found, replace the ESM in accordance with the Service Information. Refer to SHIFTER, TRANSMISSION, REMOVAL AND INSTALLATION, 8HP50/850RE or SHIFTER, TRANSMISSION, REMOVAL AND INSTALLATION, 8HP75 .
  - Perform the ESM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.
4. Check for any Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the ESM VERIFICATION TEST. Refer to ELECTRONIC SHIFT MODULE (ESM) VERIFICATION TEST .
  No
  - Perform the ESM VERIFICATION TEST. Refer to ELECTRONIC SHIFT MODULE (ESM) VERIFICATION TEST .
  - Test complete.