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.
DTC P16BB
DTC P16BB : Alternator B Terminal Circuit Low Voltage
NOTE: Before you troubleshoot, review the general troubleshooting information .
| DTC Description | Confirmed DTC | Pending DTC | Freeze Frame |
|---|---|---|---|
| P16BB Alternator B Terminal Circuit Low Voltage |
DTC (PGM-FI)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Start the engine.
-4. Check under these conditions:
- A/C on
- Temperature control at maximum cool
- Blower fan at maximum speed
- Headlights on high beam
- Rear window defogger on
-5. Hold the engine speed at 2, 000 rpm without load (CVT in P or N, M/T in neutral) for 1 minute.
-6. Check for Pending or Confirmed DTCs with the HDS.
DTC Description Confirmed DTC Pending DTC Freeze Frame P16BB Alternator B Terminal Circuit Low Voltage Is DTC P16BB indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the alternator and the 12 volt battery terminal fuse box. Also check the 12 volt battery performance . If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot .
- +B terminal check
-1. Check for poor connections or loose terminals at the alternator and the 12 volt battery terminal fuse box (ACG+B line).
Are the connections and terminals OK?
YES
Go to step 3.
NO
Repair the connections or the terminals.
- Open wire check (ACG +B line)
-1. Check for an open in the wire between the alternator and the 12 volt battery terminal fuse box at the engine harness.
Is the harness OK?
YES
NO
Repair an open in the ACG +B wire between the alternator and the 12 volt battery terminal fuse box.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.