Posted: 1/27/2011 11:29:11 AM EDT
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If this goes bad, what sort of symptoms will it show? The car is acting like the alternator is dead. Lights dim, sluggish on acceleration, but the engine code for the check engine light says it's the knock sensor. Could poor combustion from low voltage cause this code to come up? |
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Fix the charging system first. Low system voltage will cause all kinds of misdiagnosis. First thing clean the battery terminals with a terminal brush make sure the terminals tighten down securely. Check all connections to the starter and to ground. If you can remove the cell caps, check in the battery for fluid. If the fluid is below the plates top them off and then charge the battery overnite with a 6/2A battery charger. You can check specific gravity with a floating ball tester. Get one from NAPA so you can get a better quality one. Follow the instructions if you find one or two cells with lower specific gravity the battery is bad. Here is a DIY test for charging systems. If you have a volt meter test battery voltage with key off engine off(KOEO). It should be around 12 volts +or- one half voltage. Record it. Start the vehicle and test the voltage after the vehicle has ran for 5 minutes. Voltage across the battery terminals should be 13V to 14.5Vs. If it is almost the same as the KOEO numbers your charging system is not working. This a quick test and does not completly test the charging system. Take the vehicle to a repair shop and have them test the charging system. Ask them to clear the code in the computer. If it comes back you may have other problems. Fix simple problems first it's cheaper! |
| My parents' Cavalier has the knock sensor wire completely chewed off by a squirrel or something, so it was completely not working. We had our own scanner and it came up as that. Car drove fine, but it only got driven maybe 2 weeks off and on before we fixed it. |