| Fault Code | Possible cause | Action |
| P0654 | Tachometer system fault | View & note "freeze frame" data if available. View & note "sensor" data. Ensure instrument connector is secure. Disconnect ECM and proceed to pinpoint test 1 |
Pinpoint tests
| Test | Result | Action |
| 1 Check cable and terminal integrity: - ECM pin B14 | OK | Disconnect instrument and proceed to test 2 |
| Faulty | Rectify fault, proceed to test 5 | |
| 2 Check cable for short circuit: - ECM pin B14 to ground | OK | Proceed to test 3 |
| Short circuit | Locate and rectify wiring fault, proceed to test 5 | |
| 3 Check cable continuity: - Instrument pin 1 to ECM pin B14 - Instrument pin 10 to earth - Instrument pin 2 to alarm control unit pin 1 | OK | Proceed to test 4 |
| Open circuit | Locate and rectify wiring fault, proceed to test 5 | |
| 4 Check cable for short circuit: - ECM pin B14 to ECM pin A20 | OK | Renew instruments, proceed to test 5 |
| Short circuit | Locate and rectify wiring fault, proceed to test 5 | |
| 5 Reconnect harness, clear fault code and run diagnostic tool function test to visually verify operation of tachometer | OK | Action complete - quit test |
| Fault still present | Contact Triumph service |
Circuit diagram
