Code 5 - Map Sensor
- Turn ignition off. Remove EFI/ECU fuse in under-hood relay panel for 10 seconds to reset ECU. Start engine and hold at idle. Verify if CHECK ENGINE light is on and if LED is flashing Code 5. If LED is not flashing Code 5, problem is intermittent. Test drive vehicle and check light again.
- If CHECK ENGINE light is on and Code 5 is still present, turn ignition off. Install "T" fitting in No. 2 vacuum hose between vacuum manifold and MAP sensor. Connect vacuum gauge to "T" fitting. See Fig 1
. Start engine. If vacuum is not present, repair as necessary. If engine vacuum is present, connect vacuum pump to "T" fitting. Apply vacuum and check if vacuum holds.
- If vacuum is held, go to step 4). If vacuum does not hold, connect vacuum pump directly to MAP sensor. Apply vacuum. If MAP sensor holds vacuum, replace vacuum hose to port. If MAP sensor does not hold vacuum, replace MAP sensor.
- Connect 3-wire test connector between MAP sensor and wiring harness. Turn ignition on. Measure voltage between White (positive) and Green (negative) sensor terminals. If reading is not about 3 volts, replace MAP sensor. If reading is about 3 volts, substitute a known good ECU. If condition is corrected, replace original ECU.
Courtesy of AMERICAN HONDA MOTOR CO., INC.