Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

NOTE:

Use the Wiring Schematics and connector end views to identify the device's ground, ignition, and serial data circuit terminals.

Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
Disconnect the appropriate component:
- B136 Exhaust Particulate Matter Sensor
- B195A Nitrogen Oxides Sensor 1
- B195B Nitrogen Oxides Sensor 2
- B195C Nitrogen Oxides Sensor 3
Test for less than 10 ohms between the test points:
- {B136 Exhaust Particulate Matter Sensor}Ground circuit terminal 1 & Ground
- {B195A Nitrogen Oxides Sensor 1}Ground circuit terminal 4 & Ground
- {B195B Nitrogen Oxides Sensor 2}Ground circuit terminal 4 & Ground
- {B195C Nitrogen Oxides Sensor 3}Ground circuit terminal 4 & Ground
- If 10 Ω or greater
1. Ignition/Vehicle OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 10 Ω
Ignition ON/Vehicle In Service Mode.
Verify a test lamp turns On between the test points:
- {B136 Exhaust Particulate Matter Sensor}Ignition circuit terminal 4 & Ground
- {B195A Nitrogen Oxides Sensor 1}Ignition circuit terminal 1 & Ground
- {B195B Nitrogen Oxides Sensor 2}Ignition circuit terminal 1 & Ground
- {B195C Nitrogen Oxides Sensor 3}Ignition circuit terminal 1 & Ground
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition/Vehicle OFF, remove the test lamp.
2. Test for less than 2 Ω in the ignition circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
1. Ignition/Vehicle OFF, remove the test lamp.
2. Connect the component disconnected in step 2.
3. Ignition - On/Vehicle - In Service Mode
4. Replace the component: Fuse
5. Verify the fuse does not open.
  - If the fuse opens and there are components connected to the circuit - Disconnect a component and repeat procedure starting at step 5.4
  - If the fuse opens with all components disconnected from the circuit - Repair the short to ground on the circuit.
  - If the fuse does not open after disconnecting a component from the circuit - Replace the component disconnected last.
  - Go to next step: If the fuse does not open with all components connected.
6. All OK.
- Go to next step: If the test lamp illuminates
Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. Disconnect the harness connectors of the device setting the DTC. It may take up to 10 min for all vehicle systems to power down.
Test for less than 2 Ω in each of the Powertrain high speed GMLAN serial data circuits end to end between the appropriate component and the device setting the DTC.
- If 2 Ω or greater
  Repair the open/high resistance in the serial data circuit between the appropriate component and the device setting the DTC.
- Go to next step: If less than 2 Ω
Reconnect the harness connectors at the device setting the DTC.
Test for 110 - 130 Ω between each pair of Powertrain high speed GMLAN serial data circuits at the appropriate component.
- If less than 110 Ω
  Refer to DTC U0076 to test for a short to ground or a short between the serial data circuits.
- If greater than 130 Ω
  Refer to DTC U0076 to test for an open/high resistance in the serial data circuit.
- Go to next step: If between 110 - 130 Ω
Replace the appropriate component:
- B136 Exhaust Particulate Matter Sensor
- B195A Nitrogen Oxides Sensor 1
- B195B Nitrogen Oxides Sensor 2
- B195C Nitrogen Oxides Sensor 3