| Fault Code | Possible cause | Action |
| P0505 | ISC stepper motor/ wiring fault | View & note diagnostic tool "freeze frame" data if available. View & note diagnostic tool "sensor" data. Ensure sensor connector is secure. Disconnect ECM and proceed to pinpoint test 1 |
Pinpoint tests
| Test | Result | Action |
| 1 Check cable and terminal integrity: - ECM pin B23 - ECM pin B07 - ECM pin B11 - ECM pin B03 | OK | Proceed to test 2 |
| Faulty | Rectify fault, proceed to test 7 | |
| 2 Check resistance value: - ECM pin B23 to ECM pin B07 - ECM pin B11 to ECM pin B03 | 4Ω to 12Ω | Disconnect stepper motor and proceed to test 3 |
| Open circuit | Proceed to test 4 | |
| Short circuit | Disconnect stepper motor and proceed to test 5 | |
| 3 Check cable for short circuit: - ECM pin B23 to earth - ECM pin B07 to earth - ECM pin B11 to earth - ECM pin B03 to earth | OK | Proceed to test 7 |
| Short circuit | Locate and rectify wiring fault, proceed to test 7 | |
| 4 Check cable continuity: - ECM pin B23 to stepper motor pin A - ECM pin B07 to stepper motor pin A1 - ECM pin B11 to stepper motor pin В - ECM pin B03 to stepper motor pin B1 | OK | Proceed to test 6 |
| Open circuit | Locate and rectify wiring fault, proceed to test 7 | |
| 5 Check cable for short circuit: - ECM pin B23 to ECM pin B07 - ECM pin B11 to ECM pin B03 | OK | Proceed to test 6 |
| Short circuit | Locate and rectify wiring fault, proceed to test 7 | |
| 6 Check stepper motor resistance: - Motor pin A to motor pin A1 - Motor pin В to motor pin B1 | 4Ω to 12Ω | Proceed to test 7 |
| Faulty | Renew stepper motor, proceed to test 7 | |
| 7 Reconnect harness, clear fault code and run diagnostic tool function test to visually verify operation of stepper motor | OK | Action complete - quit test |
| Fault | Contact Triumph service |
Circuit diagram
