Mack Trouble Code – 4375 Data Valid But Above Normal Operational Range
Details
- Park vehicle on level surface, turn ignition OFF, set parking brake and block wheels.
- Connect scan tool, turn ignition ON with engine OFF and record all circuit related active and inactive fault codes. Turn ignition OFF. If any codes are Voltage Supply Codes. Diagnose these codes first. Go to step 17. If no Voltage Supply Codes exist go to next step.
NOTE: If multiple active fault codes are present a shared open or shorted supply, return, or ground circuit is possible.
- Verify there is no visible damage to component or hoses/lines connected to component. Ensure correct DEF fluid level/proper component operation. See Mack – MP7 – EPA07/EPA10 – Intake, Exhaust & Turbocharger for component operation. Repair/replace faulty components; go to step 17. If components are good go to next step.
- Disconnect ACM harness connector and inspect wiring harness connectors and Terminals for damage, moisture, proper Terminal tension, and corrosion. If damage is found, clean and repair as required. Go to step 16. If no damage is found, go to next step.
- Disconnect Aftertreatment DEF Pump harness connector and inspect wiring harness connectors and Terminals for damage, moisture, proper Terminal tension, and corrosion. If damage is found, clean and repair as required. Go to step 16. If no damage is found, go to next step.
- Connect ACM connector. Disconnect DEF pump harness connector. Turn ignition ON. Measure voltage between DEF pump harness connector SPLY1 ACTUATORS voltage supply circuit Terminal 9 and PUMP component return circuit Terminal 8. Record voltage measurement. Turn ignition OFF. If voltage is 12 Volts, replace pump. Go to step 16. If voltage is NOT 12 Volts, go to next step.
NOTE: Measure towards ACM.
- Disconnect ACM connector. Turn ignition ON. At ACM, measure voltage between ACM SPLY1 ACTUATORS Terminal 52 and ACM PUMP Terminal 8. Record voltage measurement, turn ignition OFF. If voltage is 12 Volts, go to next step. If voltage is NOT 12 Volts, contact an authorized OEM service center to verify a possible ACM malfunction. Go to step 16.
NOTE: Measure towards ACM.
- With ACM connector and DEF pump harness connector disconnected, measure pump resistance between PUMP CTRL Terminal 10 and SPLY1 ACTUATORS Terminal 9 of pump connector. Verify resistance is 10 Ohms. If resistance is NOT 10 Ohms, clean/replace sensor. Go to step 16. If resistance is 10 Ohms, go to next step.
NOTE: Measure towards sensor.
- With ACM connector and DEF pump harness connector disconnected, measure pump resistance between PUMP CTRL Terminal 10 and PUMP Terminal 8 of pump connector; verify resistance is 10 Ohms. If resistance is NOT 10 Ohms clean/replace sensor. Go to step 16. If resistance is 10 Ohms, go to next step.
NOTE: Measure towards sensor.
- With ACM connector and DEF pump harness connector disconnected, measure resistance between DEF PUMP CTRL Terminal 7 Signal Circuit harness connector and a good ground. Repeat this step for DEF pump harness connector SPLY1 ACTUATORS Terminal 9 and PUMP Terminal 8. If resistance is less than 100K Ohms repair short to ground. Go to step 16. If resistance is more than 100K Ohms go to next step.
NOTE: Measure towards ACM.
- With ACM connector and DEF pump harness connector disconnected, measure signal circuit resistance between ACM PUMP CTRL Terminal 7 Signal Circuit in harness connector and PUMP CTR Terminal 10 in pump harness connector. If resistance is more than 10 Ohms repair or replace open circuit or excessive resistance in harness, go to step 16. If resistance is less than 10 Ohms go to next step.
NOTE: Measure across harness.
- With ACM connector and DEF pump harness connector disconnected, measure signal circuit resistance between ACM SPLY1 ACTUATORS Terminal 52 in harness connector and ACM SPLY1 ACTUATORS Terminal 9 in pump harness connector. If resistance is more than 10 Ohms repair or replace open circuit or excessive resistance in harness, go to step 16. If resistance is less than 10 Ohms go to next step.
NOTE: Measure across harness.
- With ACM connector and DEF pump harness connector disconnected, measure return circuit resistance between ACM PUMP Terminal 8 in harness connector and ACM PUMP Terminal 8 in pump harness connector. If resistance is more than 10 Ohms repair or replace open circuit or excessive resistance in harness, go to step 16. If resistance is less than 10 Ohms go to next step.
NOTE: Measure across harness.
- With ACM connector and DEF pump harness connector disconnected, measure signal circuit resistance between ACM PUMP CTRL Terminal 7 and all other Terminals on ACM Harness connector. Measure return circuit resistance between ACM PUMP Terminal 8 and all other Terminals on same ACM Harness connector. Measure supply circuit resistance between ACM SPLY1 ACTUATORS Terminal 52 and all other Terminals on same ACM Harness connector. Verify resistance is 10 Ohms. If resistance is NOT 10 Ohms repair short in harness and go to step 16. If resistance is 10 Ohms go to next step.
NOTE: Measure towards harness.
- If FMI 0 is active connect scan tool and with ignition ON watch that circuit responds correctly after 30 seconds. If circuit does NOT respond correctly repair/replace DEF pump, go to next step. If circuit responds correctly go to step 16.
- Connect ACM and Aftertreatment DEF Pump harness connectors, go to next step.
- Clear fault codes and verify code is NOT active. If code is still active, perform diagnostic steps again. If code returns, and if unable to find cause, DEF pump may be faulty. Contact an authorized OEM service center for verification of diagnosis and further information.
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