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.
Alternator FR Signal Circuit Troubleshooting
2010 Acura TL FWD V6-3.5LSECTION Alternator FR Signal Circuit Troubleshooting
Alternator FR Signal Circuit Troubleshooting
1. Start the engine, and let it idle.
2. Monitor the ALTERNATOR in the DATA LIST with the HDS.
3. Check if the indicated percentage varies when the headlight switch is turned on.
Does the percentage vary?
YES -
The alternator signal circuit is OK.οΏ½
NO -
Go to step 4.
4. Turn the headlight switch off, and turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.
5. Jump the SCS line with the HDS.
6. Disconnect the alternator 4P connector.
7. Disconnect ECM/PCM connector C (49P).
8. Check for continuity between ECM/PCM connector terminal C44 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM/PCM (C44) and the alternator.οΏ½
NO -
Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM Initial Inspection and Diagnostic Overview, then recheck. If the symptom/indication goes away and the ECM/PCM was updated, troubleshooting is complete. If the symptom/indication goes away and the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair.οΏ½
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.