Fault Code | Possible cause | Action |
P0638 | 2nd throttle actuator motor / wiring fault | View & note «freeze frame» data if available. View & note «sensor» data. Ensure actuator connector is secure. Disconnect ECM and proceed to pinpoint test 1 |
Pinpoint tests
Test | Result | Action |
1 Check cable and terminal integrity: - ECM pin B21 - ECM pin B22 - ECM pin B12 - ECM pin B04 | OK | Proceed to test 2 |
Faulty | Rectify fault, proceed to test 7 | |
2 Check resistance value: - ECM pin B21 to ECM pin B22 - ECM pin B12 to ECM pin B04 | 4Ω to 10Ω | Disconnect actuator and proceed to test 3 |
Open circuit | Proceed to test 4 | |
Short circuit | Disconnect actuator and proceed to test 5 | |
3 Check cable continuity: - ECM pin B21 to ground - ECM pin B22 to ground - ECM pin B12 to ground - ECM pin B04 to ground | OK | Proceed to test 7 |
Short circuit | Locate and rectify wiring fault, proceed to test 7 | |
4 Check cable continuity: - ECM pin B21 to actuator pin A - ECM pin B22 to actuator pin A - ECM pin B12 to actuator pin В - ECM pin B04 to actuator pin В | OK | Proceed to test 6 |
Open circuit | Locate and rectify wiring fault, proceed to test 7 | |
5 Check cable for short circuit: - ECM pin B21 to ECM pin B22 - ECM pin B12 to ECM pin B04 | OK | Proceed to test 6 |
Short circuit | Locate and rectify wiring fault, proceed to test 7 | |
6 Check actuator resistance: - Sensor pin A to sensor pin A - Sensor pin В to sensor pin В | 4Ω to 10Ω | Proceed to test 7 |
renew actuator and proceed to test 7 | ||
7 Reconnect harness, clear fault code. Run diagnostic tool function test to visually verify operation of actuator | OK | Action complete, quit test |
Fault still present | Contact Triumph service |
Circuit diagram
![](https://motoinstruction.ru/img/triumph/7/114431.jpg)