Code 6, Coolant (TW) Sensor
- Turn ignition off and disconnect alternator sense fuse in under-hood relay box for 10 seconds to reset ECU. Start engine and observe PGM-FI warning light. If light is off, problem is intermittent. Test drive and check again.
- If light is on, warm engine to normal operating temperature (cooling fan on). Disconnect C102, C103, C303 and C305 connectors. See Fig 1
. Measure resistance from Red/White wire of C103 connector to Green/White wire of C102 connector.
- If resistance is 200-400 ohms, go to next step. If resistance is not to specification, check Red/White or Green/White wire between coolant sensor and connectors C102 and C103 for open or short. If wires are okay, replace sensor.
- Measure voltage between ground and Red/White wire of C303 connector. If reading is not about 5 volts, go to step 6). If reading is about 5 volts, measure voltage between Red/White (pos.) wire of C303 connector and Green/White (neg.) wire of C305 connector.
- If voltage is not about 5 volts, repair open Green/White (neg.) wire between ECU terminal C14 and C305 connector. If voltage reading is correct, substitute a known good ECU. If condition is rectified, replace original ECU.
- If voltage reading in step 4), between ground and Red/White wire of C303 connector, was not about 5 volts, turn ignition off. Connect system checker harness between ECU and ECU connector. Turn ignition on. Measure voltage between terminal C6 (pos.) and C14 (neg.) If voltage reading is about 5 volts, repair open Red/White wire between ECU terminal C6 and C303 connector.
- If reading is not about 5 volts, disconnect "C" connector from right side wire harness only, not the ECU. Measure voltage between terminals C6 (pos.) and C14 (neg.). If reading is now about 5 volts, repair short in Red/White wire between ECU terminal C6 and C303 connector.
- If voltage reading is still not about 5 volts, substitute a known good ECU. If condition is rectified, replace original ECU.
Courtesy of AMERICAN HONDA MOTOR CO., INC.