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.
Parasitic Draw Check
Special Tools Required
LH41 AC/DC low current clamp meter, FLULH41A**: Available through the Honda Tool and Equipment Program, 888-424-6857
- Parasitic draw check 1
-1. Make sure the 12 volt battery is fully charged, and that all the vehicle's electrical accessories are turned off.
-2. Order to recognize that the hood is closed, disconnect the hood latch switch 2P connector and then connect the hood latch switch 2P connector terminals No. 1 and No. 2 with a jumper wire.
-3. Turn the vehicle to the ON mode.
-4. Turn the vehicle to the OFF (LOCK) mode.
-5. Get out of the vehicle, and close all doors and trunk securely.
-6. Lock the doors with the keyless remote.
-7. Make sure the front individual map lights and the ceiling light are turned off, and the security alarm system is armed.
-8. Wait for at least 20 minutes.
-9. Attach the LH41 AC/DC low current clamp meter (A) to the 12 volt battery ground cable (B). Follow the equipment manufacturer's instructions, then measure the parasitic draw.
NOTE: If you are using a digital multimeter: go to step 2.
Threshold of the parasitic draw 27.0 mA Is the measured valued less than the threshold?
YES
Intermittent failure, the system is normal at this time.
NO
Go to step 3.
- Parasitic draw check 2:
Check the following items before measuring:
- Set the multimeter dial to the DCA (direct current amps) range.
- Plug the red test probe into the red A (Amps) jack, and plug the black test probe into the COM jack.
- To avoid blowing an input fuse, start by setting the range above 10 A.
-2. Loosen the nut (A) on the 12 volt battery negative terminal.
NOTE: Follow the instructions exactly to avoid disconnecting the 12 volt battery ground cable terminal from the 12 volt battery negative terminal.
-3. Connect the red (+) test lead (A) to the 12 volt battery ground cable terminal (B).
-4. Carefully slide the 12 volt battery ground cable terminal upwards from the 12 volt battery negative terminal post to maintain contact and avoid disconnection. Then connect the black (-) test lead (C) to the 12 volt battery negative terminal post.
-5. Disconnect the 12 volt battery ground cable terminal (A) from the 12 volt battery negative terminal.
-6. Measure the parasitic draw.
NOTE: If the measured value is over the threshold, wait 20 minutes and recheck.
Threshold of the parasitic draw 27.0 mA Is the measured valued less than the threshold?
YES
Intermittent failure, the system is normal at this time.
NO
Go to step 3.
- Electrical equipment check
-1. Check if there are any aftermarket electrical accessories installed on the vehicle.
Are there any aftermarket electrical accessories installed?
YES
Remove any installed aftermarket accessories and do parasitic draw tests again.
NO
Go to step 4.
- Parasitic draw check 3
-1. Remove the No. A27 fuse while the test leads are connected, and measure the parasitic draw.
Threshold of the parasitic draw 14.0 mA Is the measured valued less than the threshold?
YES
Go to step 5.
NO
Go to step 6.
- Parasitic draw check 4
-1. Install the No. A27 fuse .
-2. Short the B-CAN_H line to B-CAN_L line with a jumper wire while the test leads are connected.
-3. Turn the vehicle to the ON mode and then the OFF (LOCK) mode.
-4. Get out of the vehicle and close all the doors.
-5. Wait for at least 40 seconds.
-6. Measure the parasitic draw.
Threshold of the parasitic draw 27.0 mA Is the measured valued less than the threshold?
YES
Disconnect the control units from the B-CAN circuit one at a time, perform step 3-6 above, then measure the parasitic draw. Do the input test for the control unit that reduced the parasitic draw to 27.0 mA or less when disconnected.
NO
Disconnect the control units from the back-up fuse circuit one at a time, perform step 3-6 above, then measure the parasitic draw. Replace the control unit that reduced the parasitic draw to 27.0 mA or less when disconnected.
- Parasitic draw check 5
-1. Remove the No. A2-1 and No. A5-5 fuses while the test leads are connected.
-2. Turn the vehicle to the ON mode and then the OFF (LOCK) mode.
-3. Get out of the vehicle and close all the doors.
-4. Wait for at least 40 seconds.
-5. Measure the parasitic draw.
Threshold of the parasitic draw 27.0 mA Is the measured valued less than the threshold?
YES
Go to step 7.
NO
Remove the fuse(s) one at a time, and identify the parts which excessively consume current.
- Parasitic draw check 6
-1. Install the No. A2-1 and No. A5-5 fuses .
-2. Disconnect under-dash fuse/relay box connector D (27P) and relay circuit board connector A (2P) one at a time while the test leads are connected, and measure the parasitic draw.
Threshold of the parasitic draw 27.0 mA Is the measured valued less than the threshold?
YES
Replace the under-dash fuse/relay box or the relay circuit board .
NO
Repair a short to ground in the wire between the No. A2-1 fuse and the relay circuit board.
NO
Repair a short to ground in the wire between the No. A5-5 fuse and the under-dash fuse/relay box.
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.