2 SPN 521049/FMI 31 - GHG17 DEF Inducement DEF Lamp Active Table 1. SPN 521049/FMI 31 Description This Code Sets When There is a Code Present for the Diesel Exhaust Fluid (DEF) Tank Level, DEF Dosing Unit, DEF Pump, NOx Sensors, Blocked DEF Line, DEF Quality, NOx Efficiency, Selective Catalyst Reduction (SCR) Harness and/or SCR Sensor. WARNING!!: ⚠️⚠️⚠️Always use the proper tools and safety equipment to perform this job. Failure to perform the job correctly can result in personal injury.

EPA07/10/GHG14 DDEC VI/10 Electronics and Troubleshooting Manual (DDC-SVC-MAN-0084) | 505 SPN 4374 (ACM) (GHG14) | 505.1 SPN 4374/FMI 0 – GHG14

Description	This Code Sets When the Diesel Exhaust Fluid (DEF) Pump Speed is Higher than Normal For a Given DEF Pressure
Monitored Parameter	DEF Pump Speed, DEF Pressure
Monitor Sequence	None
Execution Frequency	Continuous When Enabling Conditions Met
Typical Duration	Continuous Until Resolved
Dash Lamps	MIL, CEL
Engine Reaction	Derate 25%
Verification	SCR ADS Self-Check

Possible causes:

Restriction in the DEF line between the DEF tank and the DEF pump
Restriction in the DEF line between the DEF pump and the DEF dosing unit
Air in the DEF line between the DEF tank and the DEF pump
Restriction in the DEF pump
Failed DEF pump

Check as follows:

Customers in colder climates where winter ambient air temperatures generally stay below -11° C (12°F) need to verify that the DEF is not frozen before troubleshooting this fault code.

Connect DiagnosticLink^® .

Turn the ignition ON (key ON, engine OFF).

Check for multiple codes. Are codes SPN 4334/FMI 3, 4, SPN 4375/FMI 3, 4, or SPN 3361/FMI 3, 4, 5 also present?
1. Yes; diagnose and repair the other fault codes first. Verify repair.
1. No; Go to step 4.

Turn the ignition OFF.

Inspect the DEF tank vent tube. Is there any blockage or restriction?
1. Yes; clear the restricted vent tube. Go to step 6.
1. No; Go to step 6.

Using DEF test strip A0005850202, check for diesel fuel or oil contamination of the DEF fluid. Does the test strip indicate contamination?
1. Yes; replace the following components and refill the system with new DEF:
  - DEF tank
  - DEF tank header
  - DEF supply line from the DEF tank to the DEF pump
  - DEF line from the DEF pump to the DEF dosing unit
  - DEF return line from the DEF dosing unit to the DEF tank
  - DEF pump
  - DEF dosing unit
1. No; Go to step 7.

Inspect the DEF line that runs from the DEF pump to the DEF dosing unit. Is the DEF line damaged, pinched, or kinked?
1. Yes; replace the DEF line from the DEF pump to the DEF dosing unit.
1. No; Go to step 8.

Inspect the DEF line that runs from the DEF tank to the DEF pump. Is the DEF line damaged, pinched, or kinked?
1. Yes; replace the DEF line from the DEF tank to the DEF pump.
1. No; Go to step 9.

Disconnect the DEF supply line at the dosing unit. Fill the graduated cylinder supplied in DEF test kit (P/N: W060589001900) with water. Place the end of the DEF line into the graduated cylinder as far as possible.

NOTE: Place the graduated cylinder in a secondary container to catch over flowing DEF fluid, making sure you still have clear sight of the end of the DEF line.

Using DiagnosticLink, perform the Selective Catalyst Reduction Airless Dosing System (SCR ADS) Self-Check routine. When the service routine is running, visually inspect the DEF line for continuous air bubbles coming from the line and DEF flow.

Were any bubbles coming from the DEF pump supply line indicating a crack in the DEF pump feed line?
1. Yes; replace the DEF supply line from the DEF tank to the DEF pump. Verify repair.
1. No; Go to step 12.

The RS SUPPLY KIT contains all the necessary parts for steps 12-15.

Using the DEF/Doser Kit , replace the DEF pump module filter. Go to step 13.

Replace the DEF pump inlet screen. Go to step 14.

Replace DEF Pressure Relief Valve (PRV). Go to step 15.

Replace DEF dosing unit inlet screen. Go to step 16.

NOTE: If air pressure is greater than 827 kPa (120 psi), use a pressure regulator.

Prime pump with shop air. Using a rubber tipped air gun to seal around the DEF pump inlet fitting, apply clean regulated shop air to the DEF pump inlet fitting for three to five seconds.

Connect all DEF lines and electrical connections. Go to step 18.

Perform Selective Catalytic Reduction Airless Dosing System (SCR ADS) Self-Check Routine to prime the system. Did the SCR ADS test pass?
1. Yes; clear the codes and release the vehicle.
1. No; replace the DEF pump.

ACM Fault Codes | MDEG GHG17

Page | 1

Circuit Fault

Rationality Fault

Engine Protection Fault

Component Broadcasted Fault

Communication Data Fault

Information Fault

SPN FMI ACM FAULT CODE DESCRIPTION MDEG - GHG17

108 13 Ambient Air Pressure Signal Not Available via CAN

110 9 Coolant Temperature Signal Not Available via CAN

168 1 Battery Voltage Low

168 0 Battery Voltage High

171 13 Ambient Air Temperature Signal Not Available via CAN Download marg crack software.

190 9 Engine Speed Signal Not Available via CAN

513 9 Actual Tourque Signal Not Available via CAN

625 9 PT-CAN Heartbeat Missing

625 2 CPC Message not Received or Stopped Arriving

1033 2 ACM2.1 engine hours data erratic, intermittent or incorrect

1231 9 MCM CAN1 Signal Missing

1669 9 CAN4 Signal Missing

Freightliner Code Spn 4374 Fmi 0

1761 2 DEF Tank Level Sensor Rationality

1761 4 DEF Tank Level Sensor Circuit Failed Low

Txid: 61 Spn: 4374 Fmi: 0

1761 3 DEF Tank Level Sensor Circuit Failed High

1761 18 DEF Tank Level 1 - Empty

1761 31 DEF Tank Level 3 - Low

3031 4 DEF Tank Temperature Sensor Circuit Failed Low

3031 3 DEF Tank Temperature Sensor Circuit Failed High

3031 10 DEF Tank Temperature Sensor Circuit Range/Performance

Code Spn 4374 Fmi 0

3056 2 SCR Inlet Nox Sensor - Error

3057 2 SCR Outlet Nox Sensor - Error

3216 13 SCR Inlet Nox Sensor Signal Not Available

Detroit Spn Fault Codes

3216 10 Nox Raw sensor signal erratic

Spn 2011 Fmi 9 International

3216 16 Engine Out NOx Sensor drifted low