DTC 16
DTC 15 : Heater Water Temperature Sensor systemHeater Water Temperature Sensor Circuit Part 1:
Heater Water Temperature Sensor Circuit Part 2:
DTC SET CONDITION
- DTC 15 is set if there is a defective connector connection, or if there is an open circuit in the harness.
- DTC 16 is set if there is a short circuit in the heater water temperature sensor input circuit.
TROUBLESHOOTING HINT
- Malfunction of connector.
- Malfunction of the harness.
- Malfunction of the heater water temperature sensor.
- Malfunction of the A/C-ECU.
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool MB991958, check data list.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector. 2. Ignition switch: ON
3. Set scan tool MB991958 to the data reading mode.
Item 15: heater water temperature sensor.
- Check that the heater water temperature sensor matches the displayed value on the scan tool.
NOTE: When this DTC is set and the system is fail-safe status, the value of service data displays.6 degrees C (21 degrees F).
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?
YES: Replace the A/C-ECU. Then go to Step 5.
NO: Go to Step 2.
STEP 2. Check A/C-ECU connector C-25 and heater water temperature sensor connector C-29 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Are A/C-ECU connector C-25 and heater water temperature sensor connector C-29 in good condition?
YES: Go to Step 3.
NO: Repair or replace the connector. Then go to Step 5.
STEP 3. Check the wiring harness between A/C-ECU connector C-25 (terminal 4 and 20) and heater water temperature sensor connector C-29 (terminals 2 and 1).
NOTE: Also check intermediate connector C-30 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-30 is damaged, repair or replace the connector as described in Harness Connector Inspection.
Q: Is the wiring harness between A/C-ECU connector C-25 (terminal 4 and 20) and heater water temperature sensor connector C-29 (terminals 2 and 1) in good condition?
YES: Go to Step 4.
NO: Repair the wiring harness. Then go to Step 5.
STEP 4. Check the heater water temperature sensor.
1. Disconnect the heater water temperature sensor connector C-29.
2. When the resistance between the sensor terminals is measured under two or more temperature conditions, the resistance should approximately satisfy the illustrated values.
NOTE: The temperature conditions when checking should not exceed the range shown in the diagram.
Q: Is the heater water temperature sensor in good condition?
YES: Replace the A/C-ECU. Then go to Step 5.
NO: Replace the air thermo sensor. Then go to Step 5.
STEP 5. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Connect scan tool MB991958 to the data link connector
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?
YES: The procedure is complete.
NO: Return to Step 1.