DTC B1229 or DTC indicator E and AUTO: An Open in the Sunlight 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
Turn the ignition switch to LOCK (0), and then back to ON (II), or press the engine start/stop button to select the OFF mode, and then the ON mode
Do the self-diagnostic function 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 B1229 or E and AUTO indicated?

YES -Go to step 5

NO -Intermittent failure Check for loose wires or poor connections on the sunlight sensor circuit
Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
Disconnect the sunlight sensor 2P connector
Disconnect climate control unit connector C (20P)
Check for continuity between climate control unit connector C (20P) terminal No 14 and sunlight sensor 2P connector terminal No 2

Fig 1: Checking Continuity Between Climate Control Unit Connector C (20P) Terminal 14 And Sunlight Sensor 2P Connector Terminal 2
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 sunlight sensor
Check for continuity between climate control unit connector C (20P) terminal No 1 and sunlight sensor 2P connector terminal No 1

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

Is there continuity?

YES -Go to step 10

NO -Repair open in the wire between the climate control unit and the sunlight sensor
Reconnect the sunlight sensor 2P connector
Reconnect climate control unit connectors C (20P)
Test the sunlight sensor (see SUNLIGHT SENSOR TEST )

Is the sunlight sensor OK?

YES -Check for loose wires or poor connections at climate control unit connector C (20P) and at the sunlight sensor 2P 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 -Replace the sunlight sensor (see Sunlight Sensor Replacement )