Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSACURA2004TL AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISIDLE CONTROL SYSTEMALTERNATOR FR SIGNAL CIRCUIT TROUBLESHOOTING2006 MODEL

2004 Acura TL Automatic

2006 model

2004 Acura TL AutomaticSECTION 2006 model

Start the engine, and let it idle.
Monitor the ALTERNATOR in the DATA LIST with the HDS.
Check if the indicated percentage changes when the headlight switch is turned on.
Does the percentage vary?
1. YES -The alternator signal circuit is OK.
2. NO -Go to step 4.
Turn the headlight switch and ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect the alternator 4P connector.
Disconnect ECM/PCM connector A (31P).
Check for continuity between body ground and ECM/PCM connector terminal A12.

Fig 1: Checking Continuity Between Body Ground And ECM/PCM Connector Terminal A12
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?
1. YES -Repair short in the wire between the ECM/PCM (A12) and the alternator.
2. NO -Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/ PCM (see HOW TO TROUBLESHOOT CIRCUITS AT THE ECM/PCM ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.