DTC B2970 (6) (HVAC Control Unit)

DTC B2970 or DTC indicator 6  : A short in the mode control motor A circuit (front)

NOTE:  If other short circuit DTCs are indicated at the same time, there may be an open or short to body ground in the power (5 V) circuit.

DTCs (AC)

1. Problem verification

   -1. Clear the DTC with the HDS.

   -2. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.

   -3. Do the Self-Diagnostic Function with the HDS or the HVAC control unit .

   -4. Wait for at least 8 seconds.

   -5. Check for DTCs.

   DTC Description	DTC
   B2970 A short in the mode control motor A circuit (front)

   Is DTC B2970 or 6 indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure. Check for loose wires or poor connections on the mode control motor A circuit.

2. Determine possible failure area (SENSOR 5V line, others)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   Mode control motor A 7P connector

   -3. Turn the vehicle to the ON mode.

   -4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Mode control motor A 7P connector: disconnected
   Test point 1	Mode control motor A 7P connector (female terminals) No. 1:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5 V?

   YES 

   The SENSOR 5V wire is OK. Go to step 3.

   NO 

   Go to step  6.

3. Mode control motor A check (FR MODE/MOD-P FR line)

   -1. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Mode control motor A 7P connector: disconnected
   Test point 1	Mode control motor A 7P connector (female terminals) No. 2:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5 V?

   YES 

   The FR MODE/MOD-P FR wire is OK. Replace the mode control motor A .

   NO 

   Go to step 4.

4. Shorted wire check (FR MODE/MOD-P FR line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   HVAC control unit connector C (12P)

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	HVAC control unit connector C (12P): disconnected
   	Mode control motor A 7P connector: disconnected
   Test point 1	HVAC control unit connector C (12P) No. 3
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to body ground in the wire between the HVAC control unit and the mode control motor A.

   NO 

   The FR MODE/MOD-P FR wire is not shorted. Go to step 5.

5. Shorted wire check (FR MODE/MOD-P FR line to SENSOR(COM) line)

   -1. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	HVAC control unit connector C (12P): disconnected
   	Mode control motor A 7P connector: disconnected
   Test point 1	Mode control motor A 7P connector (female terminals) No. 2:
   Test point 2	Mode control motor A 7P connector (female terminals) No. 3:

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short in the wires between the HVAC control unit and the mode control motor A.

   NO 

   The FR MODE/MOD-P FR wire to SENSOR(COM) wire are OK. Replace the HVAC control unit .

6. Open wire check (SENSOR 5V line)

   -1. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Mode control motor A 7P connector: disconnected
   Test point 1	HVAC control unit connector A (32P) No. 5
   Test point 2	Body ground

   Is there about 5 V?

   YES 

   Repair an open in the wire between the HVAC control unit and the mode control motor A.

   NO 

   The SENSOR 5V wire is not open. Go to step 7.

7. Shorted wire check (SENSOR 5V line)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Disconnect the following connector.

   HVAC control unit connector A (32P)

   -3. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode
   	HVAC control unit connector A (32P): disconnected
   	Mode control motor A 7P connector: disconnected
   Test point 1	HVAC control unit connector A (32P) No. 5
   Test point 2	Body ground

   Is there continuity?

   YES 

   Repair a short to body ground in the wire between the HVAC control unit and the mode control motor A.

   NO 

   The SENSOR 5V wire is OK. Replace the HVAC control unit .