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About 4 months ago my battery light started coming on when I started the car. When this happened my car would run in limp mode (lack of power), well with 5-10 mins of driving the VTM light would come on for a minute, car would jerk and all power would come back. Battery light went off as well as VTM light. Rest of the day the car would run fine. This happened everyday for about 4 months. When I would make it to a car quest or auto zone, the lights would be off and no codes thrown. They would say bring it back when the light is on. Finally I got my hubby to change the battery terminals (something told me it was them) after changing them we went on vacation for a week, drove 750 miles and not ONCE did the light come on or act up. Today I went to start my car and go get it inspected and sure enough the battery light was on, and back to limp mode. Went off by time we got to garage. Passed inspection, as pulling out of garage battery light came back on. Went to auto store, put on computer, no codes but they tested battery voltage on both battery and alternator. Both not performing at right voltage. My hubby says alternator must be bad. I don't agree. Both battery and alternator just over a year old and both just tested fine 2 hours ago. I see there was another post like mine and the guy changed both parts and it didn't fix his problem either. Any ideas before I spent hundreds on parts I don't believe are the problem?
 

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Perhaps start by verifying all your main cables to and from the battery and the alternator you say you got changed a year ago. Perhaps something's come loose and/or corroded.
 

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Thank you for your suggestion. My husband did check all going to and from battery he just hasn't check connections from the alternator. We will start with all stuff from alternator. Thanks
 

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Also check ground cables from engine block to chassis both for loose connections and corrosion.

If you have a voltmeter you can easily check the battery voltage under no-load condition ~12.6V (after vehicle has been off for a while), alternator under minimum load (interior blowers and headlights off) ~14.4v, and alternator under load (headlights on and interior blowers both running full speed) ~14.2v.
 
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There is also the possibility that the code readers at the car parts stores only read generic trouble codes. You may need to have all the codes read by a reader which deciphers Honda specific codes (dealer, Honda/Acura specialty shop, or buy one for ~$180). There is also the method to jumper the OBD2 port to flash the major (but not associated minor code) on the dash.
 

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Discussion Starter #6
Also check ground cables from engine block to chassis both for loose connections and corrosion.

If you have a voltmeter you can easily check the battery voltage under no-load condition ~12.6V (after vehicle has been off for a while), alternator under minimum load (interior blowers and headlights off) ~14.4v, and alternator under load (headlights on and interior blowers both running full speed) ~14.2v.
Funny you should mention that. The guy at the parts store got under my car to check the ground wires and did say my chassis cable had corrosion on it. Do you think that could cause all these problems? We took it for inspection the day this all started again and their computer didn't pick any codes up either, and the tech had tested my battery, alternator, and starter a week ago and now my husband said my battery and alternator are bad based on his volt meter read??? I find this hard to believe seeing they were good a week ago. I seriously think there is an underlying issue here. Both of them have been replaced within the last year and another guy on here had the exact same problem with his Honda pilot and was told it was his alternator and he replaced it and the car continued to do the same thing. I am so lost. Please any help is so appreciative.
 

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The short answer to your question is yes, a bad main power/ground cable could be the cause of the electrical issues on your Pilot.

Since you have a voltmeter measure the voltage drop between the alternator output and battery positive terminal while the Pilot is turned on and drawing a large current load (turn as many things on as you can).

Perform the same measurement across the chassis to negative battery terminal connection.

Perform the same measurement from engine block to chassis cables. I’ll bet the one you mentioned has corrosion is somewhere below the starter.

If each cable is in good condition the voltage drop across it should be fairly low (less than 0.2Vdc). If you measure significantly higher voltage across the cable that means the resistance of that cable is higher than expected (not good). Replace that cable and remeasure the voltage drop across it.
 

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Discussion Starter #8
About 4 months ago my battery light started coming on when I started the car. When this happened my car would run in limp mode (lack of power), well with 5-10 mins of driving the VTM light would come on for a minute, car would jerk and all power would come back. Battery light went off as well as VTM light. Rest of the day the car would run fine. This happened everyday for about 4 months. When I would make it to a car quest or auto zone, the lights would be off and no codes thrown. They would say bring it back when the light is on. Finally I got my hubby to change the battery terminals (something told me it was them) after changing them we went on vacation for a week, drove 750 miles and not ONCE did the light come on or act up. Today I went to start my car and go get it inspected and sure enough the battery light was on, and back to limp mode. Went off by time we got to garage. Passed inspection, as pulling out of garage battery light came back on. Went to auto store, put on computer, no codes but they tested battery voltage on both battery and alternator. Both not performing at right voltage. My hubby says alternator must be bad. I don't agree. Both battery and alternator just over a year old and both just tested fine 2 hours ago. I see there was another post like mine and the guy changed both parts and it didn't fix his problem either. Any ideas before I spent hundreds on parts I don't believe are the problem?
Would a bad alternator throw a code?
 

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Check the condition of your cables first. Post #7 above.

Then check your alternator output (post #4 above).

I’d ignore the codes until you get these two resolved as both are related to the voltage the electronic components on your Pilot will see. Too high or too low a voltage can be the cause of strange electrical issues.
 
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