A 1999 Buick LeSabre that won’t start and has no OBD2 communication can be a frustrating problem. This article will guide you through the common causes, diagnostic steps, and potential solutions for this issue, helping you get your LeSabre back on the road.
Understanding the Problem: No OBD2 Communication and No Start
When your 1999 Buick LeSabre won’t start and your OBD2 scanner isn’t communicating, it indicates a problem that’s preventing the car’s computer (PCM) from powering up or communicating. This can stem from a variety of issues, from simple fuse problems to more complex wiring issues. Understanding the connection between these two symptoms is key to effective troubleshooting.
Common Causes of 1999 Buick LeSabre OBD2 No Communication No Start
Several issues can cause both a no-start condition and a lack of OBD2 communication in a 1999 Buick LeSabre. These include:
- Blown Fuses: A blown fuse related to the PCM or the OBD2 port can cause both symptoms. This is often the easiest and cheapest fix.
- Faulty Ignition Switch: A bad ignition switch can prevent power from reaching the PCM and the OBD2 port.
- Wiring Problems: Damaged or corroded wiring in the OBD2 circuit or the PCM power supply can interrupt communication and prevent the car from starting.
- Bad PCM: While less common, a faulty PCM can also be the culprit.
Diagnosing the 1999 Buick LeSabre No Communication Issue
Here’s a step-by-step guide to diagnose the problem:
- Check the Fuses: Locate the fuse box (usually under the dash or under the hood) and check the fuses related to the PCM and the OBD2 port. Consult your owner’s manual for the specific fuse locations.
- Test the OBD2 Port: Use a multimeter to check for power and ground at the OBD2 port. This will help determine if the issue is with the port itself or the wiring leading to it.
- Inspect the Ignition Switch: Check the ignition switch for any signs of damage or wear. Try starting the car in different key positions to see if the problem is intermittent.
- Examine the Wiring: Visually inspect the wiring harness leading to the PCM and the OBD2 port for any breaks, corrosion, or loose connections.
1999 Buick LeSabre OBD2 Wiring Diagram
Solutions for 1999 Buick LeSabre OBD2 and No Start Problems
Once you’ve diagnosed the problem, you can implement the appropriate solution:
- Replace Blown Fuses: If a blown fuse is the culprit, simply replace it with a new fuse of the correct amperage.
- Repair or Replace the Ignition Switch: If the ignition switch is faulty, it will need to be repaired or replaced.
- Repair Wiring Issues: Damaged or corroded wires will need to be repaired or replaced.
- Replace the PCM: If the PCM is determined to be faulty, it will need to be replaced and programmed.
Why is My 1999 Buick LeSabre Not Starting?
A no-start condition can be caused by numerous factors, including a faulty ignition switch, a dead battery, a bad starter, or a fuel system issue. However, when coupled with a lack of OBD2 communication, it often points to an electrical problem related to the PCM.
What if I Still Can’t Communicate with the OBD2 Port?
If you’ve checked all the common causes and still can’t communicate with the OBD2 port, it’s best to consult a qualified mechanic. They have the tools and expertise to diagnose more complex electrical issues.
Conclusion
A 1999 Buick LeSabre experiencing both a no-start condition and no OBD2 communication can be effectively diagnosed and repaired by systematically checking the fuses, ignition switch, wiring, and PCM. By following the steps outlined in this article, you can get your LeSabre back on the road quickly.
FAQ
- Can a bad battery cause no OBD2 communication? While a very low battery can sometimes interfere, it’s more likely a separate issue causing both symptoms.
- Where is the OBD2 port located on a 1999 Buick LeSabre? It’s typically located under the driver’s side dash, near the steering column.
- How much does it cost to replace a PCM? PCM replacement costs can vary, typically ranging from $500 to $1000 including programming.
- Can I drive my car with a bad OBD2 port? Yes, but you won’t be able to use a scanner for diagnostics.
- Do I need special tools to check the fuses? No, just a visual inspection or a simple test light is sufficient.
- What if I replace the fuse and it blows again immediately? This indicates a short circuit somewhere in the system, requiring further diagnosis.
- Can a bad alternator cause these problems? While unlikely, a faulty alternator can indirectly contribute to electrical issues over time.
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