TURBOCHARGER GP 1430523 - Caterpillar

Table 1
Diagnostic Trouble Code for SCR Catalyst Has Incorrect Inlet Temperature
J1939 Code and Description Pre-Conditions for Code Comments
4360-2
Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Erratic, Intermittent, or Incorrect - DPF outlet temperature (T2) is higher than trigger value
- Standard deviation of DPF outlet temperature (T2) is lower than trigger value
- No DTC invalidation flag
- The amount of exhaust gas accumulation after engine start is more than trigger value. Difference between DPF outlet temperature (T2) and SCR temperature is higher than trigger value depends on DPF outlet temperature for 50 seconds or more
- Set SCR temp. sensor quality flag to FALSE (Enable for NOx sensor dew point logic to substitute other signal).
4360-3
Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Voltage Above Norma - Battery voltage is normal
- Key switch signal (ECM: V13 & V33, DCU: 18 terminal) is continuously activated more than 2 sec
- Starter Switch signal (ECM: V12 terminal) is not activated except within 2 sec after starter stopped
- CAN communication is normal between DCU and engine ECM Voltage of SCR Temperature sensor is 2.5 V or less for 3 seconds or more.
-Set SCR temp. sensor quality flag to FALSE (Enable for NOx sensor dew point logic to substitute other signal).
4360-4
Aftertreatment #1 SCR Catalyst Intake Gas Temperature : Voltage Below Normal Voltage of SCR Temperature sensor is 0.5 V or less for 3 seconds or more.
- Set SCR temp. sensor quality flag to FALSE (Enable for NOx sensor dew point logic to substitute other signal).
4360-15
Aftertreatment #1 SCR Catalyst Intake Gas Temperature : High - least severe (1) - Key switch signal (ECM: V13 & V33, DCU: 18 terminal) is activated
- Differences among Coolant, Ambient, and DEF Tank temperature are lower than trigger value
- No DTC invalidation flag Difference between SCR temperature and the average temperature of Coolant, Ambient, and DEF tank is higher than trigger value. This DTC is enabled when differences between 2 of 3 temperatures are lower than trigger value for 50 seconds or more
- Set SCR temp. sensor quality flag to FALSE (Enable for NOx sensor dew point logic to substitute other signal).
Follow the troubleshooting procedure in order to identify the root cause of the fault.
Illustration 1 g06150909
Table 2
Troubleshooting Test Steps Values Results
1. Check SCR Gas Temperature Sensor
A. Use a heat gun to measure the base of SCR temperature sensor and compare to the temperatures that are in Caterpillar Electronic Technician (ET).
Temperatures are approximately the same
Result: The temperatures are not approximately the same
2. Measure the Resistance Between DCU Terminals
A. Place key switch in OFF position.
B. Disconnect the connector to the DCU.
C. Measure the resistance between DCU terminals 44 and 57.
Resistance are Approximately:
0C is 201