[Snatch block]

I have a 2012 Honda Odyssey. The VSA light recently turned on and the brakes began applying pressure and did not let off. We limped to a spot to stop and shut the van down. It later started without the VSA light on. It has repeated however. We searched for codes and found ABS codes 66-1 "control unit circuit stuck off", 62-1 "millimeter wave radar sensor error", and 81-1 "current sensor 2 failure". It sounds like the ABS/VSA control module may be the culprit, a $600-$700 unit. Not sure if 81-1 is a sensor in the ABS/VSA control module or wheel speed sensor. Any ideas?

Thank you!

 

[AMTMJ]

I wouldn’t pull the trigger on the module yet. Per the manual:

Code 62: Battery voltage high
Code 66: Pressure sensor alfunction
Code 81: Modulator-control unit internal circuit malfunction

Seeing that you received a battery voltage fault, I’d troubleshoot this first, as the other two faults may be cascading as a result.

Check your battery health, check charging system voltage with engine running, and your battery connections for security and corrosion.

When was your battery last replaced? I normally get about 3 good years of life before it goes Tango Uniform.

 

[Snatch block]

I wouldn’t pull the trigger on the module yet. Per the manual:

Code 62: Battery voltage high
Code 66: Pressure sensor alfunction
Code 81: Modulator-control unit internal circuit malfunction

Seeing that you received a battery voltage fault, I’d troubleshoot this first, as the other two faults may be cascading as a result.

Check your battery health, check charging system voltage with engine running, and your battery connections for security and corrosion.

When was your battery last replaced? I normally get about 3 good years of life before it goes Tango Uniform.

Thank you for the response. The battery came with the van, it is a 2021 battery. I will clean the terminals of today. What manual are you using? I probably need to get one.

 

[AMTMJ]

I bought the Honda manual on CD off RockAuto a few years ago. Works like a champ.

While you’re in there, if you have a meter, you can check the alternator’s regulated voltage to the battery to make sure it’s not too high or low (normal is around 14.5vdc). *Edit: Make sure the electrical system is loaded up, otherwise you may only read close to 13vdc if the alternator is in low-output mode.

 

[phattyduck]

Make sure the electrical system is loaded up, otherwise you may only read close to 13vdc if the alternator is in low-output mode.

That won't happen at idle, or if the engine is cold (testing in the driveway).

-Charlie

 

[Snatch block]

12.57 v engine off.
14.27 v engine on.

 

[LaserBacon]

Both of these seem to point to the same issue and the likely culprit:

Troubleshooting for 81is the same as 66
VSA DTC Troubleshooting: 81-1

DTC 81:

Modulator-Control Unit Internal Circuit Malfunction


VSA DTC Troubleshooting: 66-1

DTC 66:

Pressure Sensor Malfunction

NOTE:
- Before you troubleshoot, check the brake pedal height, free play, and brake pedal position switch adjustment

1. Turn the ignition switch to ON (II).

2. Clear the DTC with the HDS.

3. Turn the ignition switch to LOCK (0).

4. Test-drive the vehicle at 19 mph (30 km/h) or more.

NOTE: Drive the vehicle on the road, not on a lift.

5. Check for DTCs with the HDS.

Is DTC 66 indicated?

YES -

Go to step 6.

NO -

Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting.

6. Update the VSA modulator-control unit if it does not have the latest software

7. Turn the ignition switch to LOCK (0).

8. Test-drive the vehicle at 19 mph (30 km/h) or more.

NOTE: Drive the vehicle on the road, not on a lift.

9. Check for DTCs with the HDS.

Is DTC 66 indicated?

YES -

Check for loose terminals in the VSA modulator-control unit 32P connector. If the VSA modulator-control unit was updated and the symptom/indication is still present, replace the VSA modulator-control unit

NO -

If the VSA modulator-control unit was updated, troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTCs troubleshooting.