P1169 — Voltage condition 1 fault

Diagnostic algorithm

1. Connect a professional scan tool, record P1169 and any other related codes, and note freeze-frame/live data when the fault occurred.
2. Verify battery state of charge and perform a battery/charging system test (load test or battery conductance test). Repair or replace battery/alternator as needed.
3. Inspect and clean battery terminals, main power and ground connections, and the engine/chassis ground straps. Tighten to spec.
4. Inspect fuses and power/ground relays for the ECU and the suspected circuit; replace if faulty.
5. Visually inspect wiring and connectors for damage, corrosion or pin push-out at the sensor and ECU. Repair any damaged wiring using proper splices or harness repair techniques.
6. Back-probe the sensor power and signal wires and the corresponding ECU pins. Monitor voltages with ignition on and with engine running; compare to specifications and to the values in 'signal_params'.
7. Use an oscilloscope where available to look for fast transients or intermittent spikes/drops that a meter may miss.
8. If wiring and supply are good, substitute a known-good sensor (if feasible) or temporarily bench-test the sensor to confirm operation.
9. If all external circuits test good and voltages remain out of specification at the ECU connector, consider ECU internal power fault — consult factory service info before replacing ECU.
10. Clear codes after repairs and perform a test drive to confirm repair. Monitor for recurrence and check freeze-frame if it returns.