Low 12 V auxiliary battery voltage or a poor supply to the charger or contactor control circuits; Faulty or degraded precharge resistor or precharge contactor; Corroded, damaged or loose connectors or wiring in the charger, charge port or high-voltage circuit; Fault inside the on-board charger or charger control module; Main contactor sticking or not closing properly, upsetting the precharge sequence; Voltage sensing fault in the charger or battery control unit giving wrong readings; Outdated or faulty control unit software, where the manufacturer has identified it as a known cause.

P0D26

Battery Charger System Precharge Time Too Long.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
D: AreaReserved
26: FaultThe specific fault in that area

What it means

P0D26 means the control unit monitoring the battery charger system found that the precharge phase took longer than allowed. During precharge the high-voltage circuit is brought up gradually, usually through a resistor, before the main contactors close. The control unit saw the voltage fail to reach its target within the set time, so it logged the fault. Exact thresholds and the components involved depend on the vehicle.

Symptoms

Charging will not start or stops shortly after starting
Hybrid or EV warning light, or a charging system fault message on the dash
Delay or failure when the vehicle tries to go into its ready state
Reduced power or limited operation on some vehicles
Charge port indicator showing a fault

Possible causes

Low 12 V auxiliary battery voltage or a poor supply to the charger or contactor control circuitslikely
Faulty or degraded precharge resistor or precharge contactorpossible
Corroded, damaged or loose connectors or wiring in the charger, charge port or high-voltage circuitlikely
Fault inside the on-board charger or charger control modulepossible
Main contactor sticking or not closing properly, upsetting the precharge sequencepossible
Voltage sensing fault in the charger or battery control unit giving wrong readingsrare
Outdated or faulty control unit software, where the manufacturer has identified it as a known causerare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting any related contactor, isolation, charger or communication codes
Test the 12 V battery condition and charging voltage, since low supply voltage can upset the precharge sequence
Visually inspect the charge port, charging cable and inlet for damage, moisture, burn marks or corrosion
Try a different charging source and cable to rule out a supply or equipment problem
Inspect accessible charger and high-voltage wiring and connectors for chafing, water ingress or loose fit, without touching high-voltage parts
Check for applicable manufacturer service bulletins and software updates for the model
Have a trained high-voltage technician follow the manufacturer procedure to isolate the system safely, then test the precharge resistor, contactors and charger circuits
Use live data to watch voltage rise during precharge and compare with the manufacturer specification

How to fix

Repair or replace a weak 12 V battery or fix its supply and earth connections
Repair or replace damaged wiring, connectors or the charge port
Replace a faulty precharge resistor or contactor as found by testing
Replace or repair the on-board charger or its control module if it is confirmed faulty
Update the control unit software only where the manufacturer lists it as a fix for this fault
Clear the code and road test and recharge to confirm the fault does not return

Can I keep driving?

Medium severity

If the vehicle starts and drives normally you can use it briefly to get it checked, but charging may not work and the fault could worsen. If it loses power, will not become ready or shows a high-voltage warning, stop driving and get it assessed by a trained technician.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.