DTC B10C0, B10C1: Interior Temperature Sensor System

DTC SET CONDITION

DTC B10C0 is set if there is a short circuit in the interior temperature sensor input circuit.
DTC B10C1 is set if there is a defective connector connection, or if there is an open circuit in the harness.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

The A/C-ECU, the interior temperature sensor, or connector(s) or wiring between the two may be defective.

Past trouble

If DTC B10C0 or B10C1 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) between the A/C-ECU and the interior temperature sensor. If the connectors and wiring are normal, and obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do not replace the ECU.

TROUBLESHOOTING HINT

Malfunction of connector.
Malfunction of the harness.
Malfunction of the interior temperature sensor.
Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tool:

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: M.U.T.-III USB Cable
MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

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.

Use scan tool MB991958 to diagnose the CAN bus lines.

(1)Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)

(2)Turn the ignition switch to "ON" position.

(3)Diagnose the CAN bus line.

Q. Is the check result satisfactory?

	Go to Step 2.

	Repair the CAN bus lines. Repair the CAN bus lines (Refer to GROUP 54C, Diagnosis-Can Bus Diagnostic Chart ).

STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set.

(1)Erase the DTC.

(2)Turn the ignition switch to "ON" position.

(3)Check if the DTC is set.

Q. Is the check result satisfactory?

	It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .

	Go to Step 3.

STEP 3. Check interior temperature sensor connector C-08 and A/C-ECU connector C-20 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are interior temperature sensor connector C-08 and A/C-ECU connector C-20 in good condition?

	Go to Step 4.

	Repair or replace the connector. Refer to GROUP 00E, Harness Connector Inspection .

STEP 4. Check the wiring harness between A/C-ECU connector C-20 (terminal 17 and 19) and interior temperature sensor connector C-08 (terminals 2 and 1).

note

Also check joint connector C-02 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-02 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection

Check the sensor signal line and earth line for open or short circuit.

Q. Is the wiring harness between A/C-ECU connector C-20 (terminal 17 and 19) and interior temperature sensor connector C-08 (terminals 1 and 2) in good condition?

	Go to Step 5.

	Repair the wiring harness.

STEP 5. Check the interior temperature sensor.

Measure the resistance between connector terminals 1 and 2 under at least two different temperatures. The resistance values should generally match those in the graph.

note

The temperature at the check should not exceed the range in the graph.

Q. Is the interior temperature sensor in good condition?

Replace the A/C-ECU. Then go to Step 6.

Replace the interior temperature sensor. Then go to Step 6.

STEP 6. 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?

	The procedure is complete.

	Return to Step 1.