Circuit/System Testing
WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition/Vehicle - Off
- Disconnect the electrical connector: X1 @ T12 Automatic Transmission
- Ignition - On / Vehicle - In Service Mode
- Test for 8.8 to 9.2 V between the test points: 9 V Reference circuit terminal 8 & Ground
- If less than 8.8 V
- Disconnect the electrical connector: K71 Transmission Control Module
- Test for infinite resistance between the test points: 9 V Reference circuit terminal 8 @ Component harness & Ground
- If less than infinite resistance - Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 ohms between the test points: 9 V Reference circuit terminal 8 @ Component harness & The other end of the circuit @ Control module harness
- If 2 ohms or greater - Repair the open/high resistance in the circuit.
- If less than 2 ohms - Replace the component: K71 Transmission Control Module
- If greater than 9.2 V
- Disconnect the electrical connector: K71 Transmission Control Module
- Ignition - On / Vehicle - In Service Mode
- Test for less than 1 V between the test points: 9 V Reference circuit terminal 8 @ Component harness & Ground
- If 1 V or greater - Repair the short to voltage on the circuit.
- If less than 1 V - Replace the component: K71 Transmission Control Module
- Go to next step: If between 8.8 and 9.2 V
- Install - EL-38522
Variable Signal Generator
- Voltage - 5 V
- Frequency - 10 kHz
- Duty Cycle - 40%
- Black lead @ Battery Negative Post
- Red lead @ Signal circuit terminal 20
- Verify the scan tool parameter: Transmission Range Control Valve Position Sensor = 2.0 to 2.3 V
- If less than 2.0 V
- Remove - EL-38522 Variable Signal Generator
- Ignition/Vehicle - Off
- Disconnect the electrical connector: K71 Transmission Control Module
- Test for infinite resistance between the test points: Signal circuit terminal 20 @ Component harness & Ground
- If less than infinite resistance - Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 ohms between the test points: Signal circuit terminal 20 @ Component harness & The other end of the circuit @ Control module harness
- If 2 ohms or greater - Repair the open/high resistance in the circuit.
- If less than 2 ohms - Replace the component: K71 Transmission Control Module
- If greater than 2.3 V
- Disconnect the electrical connector: K71 Transmission Control Module
- Ignition - On / Vehicle - In Service Mode
- Test for less than 1 V between the test points: Signal circuit terminal 20 @ Component harness & Ground
- If 1 V or greater - Repair the short to voltage on the circuit.
- If less than 1 V - Replace the component: K71 Transmission Control Module
- Go to next step: If between 2.0 and 2.3 V
- Remove the component: Automatic Transmission Fluid Pan
- Connect the electrical connector: X1 @ T12 Automatic Transmission
- Disconnect the electrical connector: X176
- Test for 8.8 to 9.2 V between the test points: 9 V Reference circuit terminal 11 @ Control module harness & Ground
- If not between 8.8 and 9.2 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 8.8 and 9.2 V
- If not between 8.8 and 9.2 V
- Install - EL-38522
Variable Signal Generator
- Voltage - 5 V
- Frequency - 10 kHz
- Duty Cycle - 40%
- Black lead @ Battery Negative Post
- Red lead @ Signal circuit terminal 10
- Verify the scan tool parameter: Transmission Range Control Valve Position Sensor = 2.0 to 2.3 V
- If not between 2.0 and 2.3 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 2.0 and 2.3 V
- If not between 2.0 and 2.3 V
- Connect the electrical connector: X176
- Disconnect the electrical connector: X177
- Test for 8.8 to 9.2 V between the test points: 9 V Reference circuit terminal 6 @ Control module harness & Ground
- If not between 8.8 and 9.2 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 8.8 and 9.2 V
- If not between 8.8 and 9.2 V
- Install - EL-38522
Variable Signal Generator
- Voltage - 5 V
- Frequency - 10 kHz
- Duty Cycle - 40%
- Black lead @ Battery Negative Post
- Red lead @ Signal circuit terminal 5
- Verify the scan tool parameter: Transmission Range Control Valve Position Sensor = 2.0 to 2.3 V
- If not between 2.0 and 2.3 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 2.0 and 2.3 V
- If not between 2.0 and 2.3 V
- Connect the electrical connector: X177
- Disconnect the electrical connector: B315A Transmission Range Control Valve 1 Position Switch
- Test for 8.8 to 9.2 V between the test points: 9 V Reference circuit terminal 1 @ Control module harness & Ground
- If not between 8.8 and 9.2 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 8.8 and 9.2 V
- If not between 8.8 and 9.2 V
- Install - EL-38522
Variable Signal Generator
- Voltage - 5 V
- Frequency - 10 kHz
- Duty Cycle - 40%
- Black lead @ Battery Negative Post
- Red lead @ Signal circuit terminal 1
- Verify the scan tool parameter: Transmission Range Control Valve Position Sensor = 2.0 to 2.3 V
- If not between 2.0 and 2.3 V
Replace the appropriate component: Automatic Transmission Wiring Harness
- Go to next step: If between 2.0 and 2.3 V
- If not between 2.0 and 2.3 V
- Test or replace the component: B315A Transmission Range Control Valve 1 Position Switch
NOTE:
When the following connector is disconnected, the ignition cannot be turned off due to lack of a valid park input to the TCM. If the ignition needs to be turned off, the connector will need to be reconnected.