Experiencing a no-start issue with your 2000 Subaru Forester can be frustrating, especially when you also find there’s no power at the OBD2 connector. This combination of symptoms can point to several potential problems, and it’s crucial to diagnose the issue systematically rather than resorting to guesswork and part swapping.
Common Causes for No Start and OBD2 Connector Power Loss
Several components could be responsible when your 2000 Subaru Forester won’t start and the OBD2 port seems dead. Let’s explore some of the most common culprits:
Crankshaft Position Sensor
The crankshaft position sensor is vital for your engine to run. It monitors the position and rotational speed of the crankshaft, sending this information to the engine control unit (ECU). The ECU uses this data to manage ignition timing and fuel injection. A faulty crankshaft sensor can lead to a no-start condition because the ECU won’t know when to fire the spark plugs or inject fuel. While it might not directly cause a loss of power to the OBD2 port, electrical issues affecting sensors can sometimes have wider reaching effects on the vehicle’s electrical system.
Camshaft Position Sensor
Similar to the crankshaft sensor, the camshaft position sensor tracks the position of the camshaft. This is crucial for sequential fuel injection and ignition timing, especially in modern engines. A failing camshaft sensor can also prevent your Subaru Forester from starting. Again, like the crank sensor, a direct link to OBD2 power loss is less likely, but related electrical system problems can’t be ruled out immediately.
Timing Belt or Chain Issues
Although less frequent, a jumped timing belt or chain can cause a sudden no-start condition. If the timing belt has skipped a tooth or broken, the crankshaft and camshaft will be out of sync. This can prevent the engine from starting and, in some cases, could potentially lead to engine damage. While not directly related to OBD2 power, a severe mechanical failure like this can sometimes manifest in unusual electrical symptoms as the system tries to compensate or shuts down.
OBD2 Connector Power Supply Problems
The OBD2 port needs power to function. A lack of power here indicates a problem in the vehicle’s electrical system. Check the fuses related to the OBD2 port and the ECU. A blown fuse is a common cause of no power to the OBD2 connector. Wiring issues, such as shorts or breaks in the power supply wire to the OBD2 port, can also cause this problem. It’s important to investigate the power circuit for the OBD2 port to ensure it’s receiving the necessary voltage.
The Importance of Proper Diagnosis
Before you start replacing parts, remember that a systematic approach to diagnosis is always more effective. As advised, blindly swapping parts can sometimes complicate the issue further and waste time and money.
Utilize a Factory Service Manual (FSM)
A Factory Service Manual (FSM) for your 2000 Subaru Forester is an invaluable resource. It provides detailed diagnostic procedures, wiring diagrams, and component locations specific to your vehicle. Following the FSM’s diagnostic steps will help you pinpoint the exact cause of the no-start and OBD2 power issue.
Don’t Overlook Basic Mechanical Checks
Before diving deep into sensor replacements or electrical troubleshooting, ensure the basics are in order. Confirm the timing belt is intact and hasn’t jumped. Check for fuel delivery and spark. Sometimes, a seemingly complex problem has a simple mechanical root cause.
Green Diagnostic Connectors
It’s worth noting the mention of green diagnostic connectors under the dash, typically used by dealerships for diagnostics. While connecting these might allow the car to run, they are not intended for normal operation and can cause other systems to behave erratically, like the cooling fans running constantly. Ensure these connectors are disconnected during regular troubleshooting.
Conclusion
When faced with a 2000 Subaru Forester that won’t start and has no power at the OBD2 connector, resist the urge to immediately replace sensors without proper testing. Begin by checking fuses and the OBD2 port’s power supply. Consult a Factory Service Manual and follow a logical diagnostic process. While crankshaft and camshaft sensors are potential culprits for a no-start condition, the lack of OBD2 power points towards an electrical supply issue that needs to be addressed first. A methodical approach will save you time and ensure you fix the real problem effectively.
References:
http://www.doityourself.com/stry/symptoms-of-a-bad-crankshaft-sensor#b
http://www.ultimatesubaru.org/forum/topic/53131-he-says-its-a-crankshaft-sensor/
http://www.ehow.com/about_5860665_bad-crank-sensor-symptoms.html
