| Fault Code | Possible cause | Action |
| P1552 | Fan relay open circuit, or short circuit to ground | View & note diagnostic tool "sensor" data. Ensure fan relay connector is secure. Disconnect ECM and proceed to pinpoint test 1 |
| P1553 | Short circuit to battery+ | Disconnect fan relay and proceed to pinpoint test 4 |
Pinpoint tests
| Test | Result | Action |
| 1 Check cable and terminal integrity: - ECM pin B10 | OK | Disconnect fan relay and proceed to test 2 |
| Faulty | Rectify fault, proceed to test 5 | |
| 2 Check cable for short circuit: - ECM pin B10 to ground | OK | Proceed to test 3 |
| Short circuit | Locate and rectify wiring fault, proceed to test 5 | |
| 3 Check cable continuity: - Fan relay pin 4 to ECM pin B10 - Fan relay pin 6 to EMS relay pin 8 | OK | Proceed to test 4 |
| Open circuit | Locate and rectify wiring fault, proceed to test 5 | |
| 4 Check cable for short circuit: - ECM pin B10 to ECM pin A20 | OK | 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 cooling fan | OK | Action complete - quit test |
| Fault still present | Contact Triumph service |
Circuit diagram
