P220B

P220B-NOx SENSOR SUPPLY CIRCUIT PERFORMANCE - BANK 1 SENSOR 2




For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation

The after treatment system is equipped with two Nox Sensors and modules. The upstream NOx Sensor 1/1 is located before the DOC/DPF Catalyst and is permanently connected to a corresponding Nox Sensor Module mounted on the right frame rail. The downstream NOx Sensor 1/2 is located at the outlet of the DOC/DPF Catalyst and is permanently connected to a corresponding Nox Sensor Module also mounted on the right frame rail. The NOx Sensors and NOx Sensor Modules are calibrated to each other and must be replaced as an assembly. The two NOx Sensor and Module assemblies are not interchangeable. The NOx Sensor Modules are smart devices and communicate with the Powertrain Control Module (PCM) over the J1939 Data Link. The NOx Sensor Modules perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst and dosing system. The PCM will illuminate the MIL lamp after the monitor runs and fails in two consecutive trips. The PCM will turn off the MIL Lamp after the monitor runs and passes for three consecutive trips.

- When Monitored:
When the engine is running and the exhaust temperature at NOx Sensor 1/2 is above 150°C (302°F).

- Set Condition:
The Powertrain Control Module detects that the voltage supply to the NOx Sensor Module 1/2 is above or below a calibrated threshold.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC
1. Start the engine and allow the DOC/DPF Catalyst intake temperature to reach 150°C (302°F).

NOTE: This can be determined by reading the temperature of the Exhaust Gas Temperature Sensor 4 with the scan tool.

2. With the scan tool check active DTCs.

Is the DTC active?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test

2. CHECK THE NOx SENSOR 1/2 POWER AND GROUND CIRCUITS
1. Turn the ignition on, engine not running.
2. Disconnect the NOx Sensor Module 1/2 harness connector.
3. Measure the voltage across the (F505) Fused Ignition Switch Output circuit and the (Z914) Ground circuit at the NOx Sensor Module 1/2 harness connector.

NOTE: Measure the voltage at key on, engine cranking, and at idle.

Does the voltage read within 1.0 Volt of battery voltage?

Yes

- Replace the NOx Sensor 1/2. Bank 1 Sensor 2
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CHECK FOR VOLTAGE AT THE (F505) FUSED IGNITION SWITCH OUTPUT CIRCUIT
1. Measure the voltage between ground and the (F505) Fused Ignition Switch Output circuit at the NOx Sensor Module 1/2 harness connector.

Does the voltage read within 1.0 Volt of battery voltage?

Yes

- Repair the (Z914) Ground circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair the (F505) Fused Ignition Switch Output circuit for an open or high resistance. If the fuse is found to be open, check the circuit for a short to the (Z915) Ground circuit or a short to chassis ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.