HARNESS AS-BRAKE 3063011 - Caterpillar

Illustration 1 g03892975
(1) Power (12V)
(2) Ground
(3) CAN2 – Low
(4) CAN2 – High
(5) Ground
(a) Terminal Layout
(b) Pre NOx Sensor
(c) Post NOx Sensor
(d) DCU ConnectorNote: 12 V power to the NOxsensors are provided from the ECM Power relay, through the NOx Sensor Fuse, through a 31 pin connector, and then to the NOx Sensors. If there is not 12 V measured at the connector, refer to the electrical schematic to find the fault on the machine (harness, relay, fuse, etc.)
Illustration 2 g03895777For 3216-1 Pre NOx Sensor Tampering and 3226-1 Post NOx Sensor Tampering, use the following troubleshooting. Note: These two tampering codes are indicating that the NOx sensor has been removed from the SCR system and is measuring ambient conditions.
Table 2
Troubleshooting Test Steps Values Results
1. Is NOx sensor is installed
Yes or No
Result: If not installed
Repair: Install and confirm if the code does not reoccur.
Result: If installed.
Proceed to Test Step 2.
2. Are there any other NOxsensor diagnostic codes
Other Codes
Result: There are other codes.
Repair: Then troubleshoot those codes.
Result: There are no other NOx sensor codes
Repair: Replace the NOx sensor.
For all other codes, use the following troubleshooting.
Table 3
Troubleshooting Test Steps Values Results
1. Measure the Voltage on the Harness
A. Disconnect NOx sensor and measure voltage on harness side between terminals 1 and 2.
Yes or No
Result: Not OK.
Proceed to Test Step 2.
Result: OK
Repair: Replace the sensor.
2. Disconnect the harness from the NOx Sensor
A. A. Check the terminals on the harness side for grounding
- For Pre NOx Sensor, #2 and #5.
- For Post NOx Sensor, #2
Yes Or No
Result: Not OK
Repair: There is a problem the harness ground. Refer to the electrical schematic to troubleshoot
Result: OK
Repair: Then the problem is on the machine side with providing power to the NOx sensor. Refer to the above isolation schematic and to machines electrical schematic to troubleshoot further.