Dash light turns on during day’s second drive

Q: I have a 1996 Acura TL 2.5 with about 89,000 miles on it. At the beginning of the first drive of the day, all of the dash lights glow and then disappear. After driving any distance—5, 25, 100 miles— and then shutting the engine off and then starting it again for the trip home, all the dash lights come on, per usual, but the anti-lock braking system light stays on.

The next day, the process starts all over.

What might be going on, and is it dangerous to have the ABS light on all the time? Braking functions seem to be normal. Thanks for any suggestions.

—Larry T. A: Larry, your Acura’s anti-lock brake system has detected a fault and is alerting you via the ABS light. It’s difficult to say why the fault doesn’t occur or isn’t recognized until a second drive of the day, but perhaps the fault is made more apparent to the system during the restart diagnostic check by under-hood or brake-system heat.

As long as your amber ABS light is the only one illuminating—not the red brake light as well—normal braking will be unaffected. However, whenever an error is noted, your anti-lock braking system will stand down and not provide its anti-lock function. Among the things that could be causing this issue are a bad connection somewhere in the ABS circuitry, a faulty wheel speed sensor, a malfunctioning hydraulic control solenoid, or even a busted ABS controller. One odd possibility could be that when you’re restarting the engine, you’re allowing it to run more than 30 seconds, perhaps to air out a hot interior, before releasing the parking brake.

Diagnostics on this system are old-school and limited, but a code can likely be retrieved by a savvy tech counting flashes of the ABS light while the service connector is jumped. My hope would be that the cause is a fairly inexpensive and easy-to-renew wheel speed sensor. ABOUT THE WRITER

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at bradbergholdt@gmail.com; he cannot make personal replies.