Rick's Free Auto Repair Advice

Caravan Overcharging

Caravan Overcharging — Diagnose and fix

Shops are reporting a common problem with a Dodge caravan overcharging issue. When it happens, you’ll see charging voltages in the 15 to almost 17-volt range. That’s high enough to boil the water out of the battery and damage electronics in the vehicle so you must correct it ASAP. You may also see a P0563 System Voltage High trouble code.

How the Caravan charging system works

The voltage regulator on these vehicles is built into the PCM. The PCM regulates field current by pulse width modulation on the ground side of the field circuit. The PCM bases its PWM field current on voltage readings from the battery cables.

Cause of Caravan Overcharging

The most common cause of Caravan overcharging

corroded ground strap

corroded ground strap

is a bad ground connection. Start by cleaning the battery terminals and posts. Then head right down to the transaxle ground strap on the driver’s side of the vehicle. You can see it from the driver’s wheel well area. In most cases, you’ll see heavy corrosion at the ground bolt or complete disintegration of the cable.

Clean off all the corrosion and replace the ground strap if it’s disintegrated. Then retest.

If that doesn’t fix the problem, check the main PCM ground. Replace if necessary.

Additional diagnosis

If you have a scan tool with live data, compare the commanded voltage regulation versus actual.

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Posted on by Rick Muscoplat

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