DTC B1225 or DTC indicator A and AUTO: An Open in the In-car Temperature Sensor Circuit

WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. However, it is still accessible from the selected car via links, so may be relevant.

Clear the DTC with the HDS
Make sure the ignition switch is in LOCK (0), or the vehicle ignition is in the OFF mode
Do the self-diagnostic with the HDS (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITH THE HDS ) or the climate control unit (see HOW TO USE THE SELF-DIAGNOSTIC FUNCTION WITHOUT THE HDS )
Check for DTCs
Is DTC B1225 or A and AUTO indicated?

YES -Go to step 5

NO -Intermittent failure Check for loose wires or poor connections on the in-car temperature sensor circuit
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Remove the in-car temperature sensor (see HUMIDITY/IN-CAR TEMPERATURE SENSOR REPLACEMENT ), and test it (see HUMIDITY/IN-CAR TEMPERATURE SENSOR TEST )
Is the m-car temperature sensor OK?

YES -Go to step 7

NO -Replace the in-car temperature sensor
Disconnect climate control unit connectors C (20P)
Check for continuity between climate control unit connector C (20P) terminal No 15 and in-car temperature sensor 4P connector terminal No 4

Fig 1: Checking Continuity Between Climate Control Unit Connector C (20P) Terminal 15 And In-Car Temperature Sensor 4P Connector Terminal 4
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 9

NO -Repair open in the wire between the climate control unit and the in-car temperature sensor
Check for continuity between climate control unit connector C (20P) terminal No 1 and in-car temperature sensor 4P connector terminal No 3

Fig 2: Checking Continuity Between Climate Control Unit Connector C (20P) Terminal 1 And In-Car Temperature Sensor 4P Connector Terminal 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Check for loose wires or poor connections at climate control unit connectors C (20P) and at the in-car temperature sensor 4P connector If the connections are good, substitute a known-good climate control unit, and recheck If the symptom/indication goes away, replace the original climate control unit (see Climate Control Unit Removal/Installation )

NO -Repair open in the wire between the climate control unit and the in-car temperature sensor