Scan tool needed to find why warning light is on

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I have a 1996 Isuzu Hombre pickup truck and the anti-lock (ABS) warning light stays on. Please advise what could cause this.

– Robert Barrett, Fort Walton Beach, Fla.

Your Hombre’s orange ABS warning light functions similarly to the more familiar check-engine light. When illuminated it means that the Electronic Brake Control Module (EBCM) has detected a fault within the ABS system’s wiring or components. The EBCM will store a diagnostic trouble code indicating the fault area and, in most cases, suspend ABS operation until the fault is repaired and code is cleared.

According to my diagnostic software, there are 18 possible codes on this ABS system, including a faulty wheel-speed sensor, control valve, pump motor, motor relay, system memory, and so on. Retrieving codes requires a scan tool, the same device used to extract engine system codes. The scan tool also can display wheel-speed sensor readings, control solenoid status and other useful operating data – all from the comfort of the driver’s seat.

This sure beats the old days when one needed to check most components or circuits directly with a voltmeter. I can’t help much further than this without attaching a scan tool to your Hombre and retrieving diagnostic information. After a code is identified, a flow chart is followed and tests are performed, pinpointing the exact cause of the failure. Keep in mind what you’ll need is a pro-level multi-function scan tool, rather than the inexpensive OBD-II generic scan tools now popular for some check-engine light issues. Due to tool and service software needs, this problem will most likely need to be fixed by a heads-up repair shop.

Your truck is safe to drive prior to repairs being made, but it will not have anti-lock brake capability. Had this been the red brake-warning light, I’d be recommending immediate repairs.

Quiz time! Let’s see if anyone has been sleeping during class :

1. Disc brake pads return to their rest position because of the use of ___.

2. Low engine vacuum indicates ___ engine load.

3. Hybrids use the ___ to generate electricity during braking.

4. Windshields are constructed of ___ glass to help retain vehicle occupants.

5. Low fluid level in the ___ can result in an illuminated brake-warning lamp.

6. Ticking noises from an engine are often caused by the ___.

7. Vehicle speed sensor information might be shared by the speedometer, PCM and ___.

8. Excessive NOx emissions are the result of excessive ___.

9. One ___ can replace several traditional V-type accessory drive belts.

10. Of the three wheel alignment angles, ___ is most critical for optimum tire wear.

Answers:

1. Square cut caliper seals

2. Higher than normal

3. Motor generator

4. Laminated

5. Brake fluid reservoir

6. Valve train

7. Cruise control system

8. Combustion chamber temperature

9. Serpentine belt

10. Toe

If you got one to three correct, I’ve apparently put you to sleep with too much techno-babble.

If you got four to seven correct: Not bad. You’re ready to tackle many home mechanic jobs, with the right tools and manual.

If you got eight to 10 correct: If your day job doesn’t work out, fixing cars professionally might just be your thing.

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