For the past couple of months, if I didn't drive the truck for a couple of days the battery would be dead or almost dead. I figured it was time to replace the battery so I purchased a new battery without having it tested (first mistake). Couple of days later I was driving in the city about 5 miles and the icon for charging system malfunction came on and the voltage was dropping quickly. It died in the middle of a n intersection during rush hour. I was able to get a jumpstart pack from AutoZone, and with it attached to the battery was able to get it running long enough to get into a parking lot. Took battery home charged it up and got the truck home.
I replaced the alternator, without having it tested (second mistake). Started the truck and within a couple of minutes the charging system malfunction light turns on again. I test the alternator and battery both are good. Then I start diagnosing the issue. Checking all wires for any signs of damage, check all grounds, but they're all good. Then I turn to the GOOGLE, found a forum that tells how to test the alternator against the PCM by using a jumper wire from the battery to a small connection on the back of the alternator, and removing the other small wire. It should tell the alternator to start charging the battery. And it did just that.
The little wires that I removed was from the PCM. By bypassing the PCM and running the jumper straight from the battery to the alternator and getting a 16v charge, I determined it was the PCM. The dealership wanted almost $1000 to replace the PCM. I was able to find it online from Flagship One inc, programmed with a lifetime warranty for $221.24. It took me less than 10 minutes to remove the old one and replace it.
For the past couple of months, if I didn't drive the truck for a couple of days the battery would be dead or almost dead. I figured it was time to replace the battery so I purchased a new battery without having it tested (first mistake). Couple of days later I was driving in the city about 5 miles and the icon for charging system malfunction came on and the voltage was dropping quickly. It died in the middle of a n intersection during rush hour. I was able to get a jumpstart pack from AutoZone, and with it attached to the battery was able to get it running long enough to get into a parking lot. Took battery home charged it up and got the truck home.
I replaced the alternator, without having it tested (second mistake). Started the truck and within a couple of minutes the charging system malfunction light turns on again. I test the alternator and battery both are good. Then I start diagnosing the issue. Checking all wires for any signs of damage, check all grounds, but they're all good. Then I turn to the GOOGLE, found a forum that tells how to test the alternator against the PCM by using a jumper wire from the battery to a small connection on the back of the alternator, and removing the other small wire. It should tell the alternator to start charging the battery. And it did just that.
The little wires that I removed was from the PCM. By bypassing the PCM and running the jumper straight from the battery to the alternator and getting a 16v charge, I determined it was the PCM. The dealership wanted almost $1000 to replace the PCM. I was able to find it online from Flagship One inc, programmed with a lifetime warranty for $221.24. It took me less than 10 minutes to remove the old one and replace it.
- Michael D., Cordova, TN, US