P1594Manufacturer-specific code

P1594 Code: Charging System Voltage Too High (Chrysler)

On Chrysler, Dodge, Jeep and Ram vehicles, the P1594 code means the charging system voltage is too high. You may see a swollen battery or one that leaks fluid. Other brands may define this number differently.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$20 to $500
Difficulty
Medium
System
Computer and Outputs
Applies to
Depends on the manufacturer

Common in: Dodge, Jeep

Updated Reviewed by Renzo Chacca

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What the P1594 code means

P1594 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it means, not the generic SAE standard. The most widespread definition is the one used by Chrysler, Dodge, Jeep and Ram. If your vehicle is another brand, confirm the code text with a scan tool that supports that manufacturer.

ManufacturerMeaning of P1594
Chrysler, Dodge, Jeep and RamCharging system voltage too high

On many Chrysler vehicles the computer controls the alternator directly.

The computer sets the P1594 code when the voltage goes above the target: a fault in the alternator field control, a bad ground or a battery in poor condition.

Before you start repairs, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1594 code symptoms

  • Very bright lights or bulbs that burn out.
  • Battery that swells or leaks fluid.
  • Charging light on.

Likely causes of the P1594 code

  1. Alternator or its field circuit. Confirm it with the tests in the diagnosis section.
  2. Engine or computer ground. This is uncommon, so rule out everything else first.
  3. Defective battery. Confirm it with the tests in the diagnosis section.

How to diagnose the P1594 code step by step

  1. Measure the voltage with the engine running.
  2. Check the grounds.
  3. Test the battery.

How to fix the P1594 code

  • Repair the grounds.
  • Replace the alternator or the battery.

Technical reference data

  • Normal charging voltage: 13.5 to 14.7 V.
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Reference values: check the manufacturer data for your vehicle.

Brand-specific notes

Overvoltage is hard on electronics and batteries, so measure the voltage early instead of waiting for the next part to fail.

P1594 on Chrysler

Common on the Dodge, Chrysler, Jeep and Ram.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives this code and confirm it with a compatible scan tool.

Frequently asked questions about P1594

What does the P1594 code mean on a Chrysler?
It means the charging system voltage is too high. You may see a swollen battery or one that leaks fluid.
Does P1594 mean the same thing on every brand?
No. It is a manufacturer-specific code, so on other brands it may not exist or may mean something different. Confirm it with a scan tool that supports your make.
Can I drive with a P1594 code?
With caution. A P1594 code means high voltage that can damage control modules and the battery, so have it checked as soon as you can.
How much does it cost to fix P1594?
Roughly $20 to $500 on a Chrysler. A ground repair is cheap, while a new alternator or battery costs more.
Will a P1594 code clear itself?
Not while the charging system keeps overcharging. After the repair, clear the code and measure the voltage again to confirm it stays in range.
What is the most common cause of P1594?
A fault in the alternator or its field circuit. A bad ground and a defective battery are the next things to check.

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Questions about the P1594 code

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