0174092 JOHNSON TRIM GAUGE ASSY.

Table 1
J1939 Code and Description CDL Code and Description Comments
7602-2
Aftertreatment #1 DEF Controller #1 Identification : Erratic, Intermittent, or Incorrect 5028-2
Aftertreatment #1 Diesel Exhaust Fluid Controller #1 Identification : Erratic, Intermittent, or Incorrect The Diesel Exhaust Fluid Control Unit (DCU) has detected a resistance outside the normal resistance of the DCU resistor.
7602-3
Aftertreatment #1 DEF Controller #1 Identification : Voltage Above Normal 5028-3
Aftertreatment #1 Diesel Exhaust Fluid Controller #1 Identification : Voltage Above Normal The DCU has detected an open circuit in the DCU resistor circuit.
7602-4
Aftertreatment #1 DEF Controller #1 Identification : Voltage Below Normal 5028-4
Aftertreatment #1 Diesel Exhaust Fluid Controller #1 Identification : Voltage Below Normal The DCU has detected a short circuit in the DCU resistor circuit.
7603-2
Aftertreatment #1 DEF Controller #2 Identification : Erratic, Intermittent, or Incorrect 5029-2
Aftertreatment #1 Diesel Exhaust Fluid Controller #2 Identification : Erratic, Intermittent, or Incorrect The DCU has detected a resistance outside the normal resistance of the DCU resistor.
7603-3
Aftertreatment #1 DEF Controller #2 Identification : Voltage Above Normal 5029-3
Aftertreatment #1 Diesel Exhaust Fluid Controller #2 Identification : Voltage Above Normal The DCU has detected an open circuit in the DCU resistor circuit.
7603-4
Aftertreatment #1 DEF Controller #2 Identification : Voltage Below Normal 5029-4
Aftertreatment #1 Diesel Exhaust Fluid Controller #2 Identification : Voltage Below Normal The DCU has detected a short circuit in the DCU resistor circuit.
Illustration 1 g06071020
Illustration 2 g06071021
The Diesel Exhaust Fluid Control Units (DCUs) are on the rear of the Pump Electronic Tank Unit (PETU).
(1) DCU 2
(2) DCU 1
(3) DCU resistor
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot the associated code before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
Result: A code is not active or logged.
Proceed to Test Step 7.
2. Check the Resistance of the Diesel Exhaust Fluid Control Unit (DCU) Resistor
A. Turn the keyswitch to the OFF position.
B. Disconnect the 86-pin connector from the affected DCU.
C. Measure the resistance between Pin 38 and Pin 39 on the DCU.
- For DCU #1, the resistance should measure 178 +/-10 ohms.
- For DCU #2, the resistance should measure 604 +/-10 ohms.
Note: The 398-5063 Probe must be used to prevent damage to the DCU connector.
Resistance
Result: The resistance measurement of the DCU resistor at the affected DCU connector was within specification.
Proceed to Test Step 7.
Result: The resistance measurement of the DCU resistor at the affected DCU connector was not within specification.
Proceed to Test Step 3.
3. Check the Resistance of the DCU Resistor
A. Turn the keyswitch to the OFF position.
B. Disconnect the 8-pin connector from the DCU resistor.
C. Measure the resistance between the following DCU resistor pins:
- For DCU #1, Pin 1 and Pin 5, the resistance should measure 178 +/-10 ohms.
- For DCU #2, Pin 2 and Pin 6, the resistance should measure 604 +/-10 ohms.
Resistance
Result: The resistance measurement of the DCU resistor was within specification.
Proceed to Test Step 4.
Result: The resistance measurement of the DCU resistor was not within specification.
Repair: A failed DCU resistor has been detected. Replace the DCU resistor.
Proceed to Test Step 7.
4. Check the Wiring between the DCU Resistor and the Affected DCU for an Open Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the 86-pin connector from the affected DCU.
C. Disconnect the 8-pin connector from the DCU resistor.
D. Measure the resistance between the following pins:
- For DCU #1, Pin 38 on