P2D78
Low Severity (Level 1)Battery Charger Control Module B Processor Performance
P2D78 usually means battery Charger Control Module B Processor Performance.
Can you still drive with P2D78?
✅Safe to drive — this is an informational or minor issue. Schedule diagnosis at your convenience.
Typical repair cost: $30 – $300
Severity Level 1 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- The battery saver/power management system is not operating as designed
- Warning light or malfunction indicator related to the battery saver/power management system is illuminated
- Diagnostic trouble code (DTC) stored in module memory
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the battery saver/power management system
Possible Causes
- Faulty battery saver relay — most common cause, test before replacing
- Damaged or corroded wiring/connector in the battery saver/power management system circuit
- Blown fuse or faulty relay for the battery saver/power management system
- Poor ground connection — check and clean all related ground points
- Control module fault — rare but possible, only consider after ruling out simpler causes
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($50-107 at shop, free at auto parts store for basic scan)
- Visually inspect the battery saver/power management system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $109 diagnostic fee at shop)
- Replace battery saver relay if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($30-300)
- Check and replace any blown fuses in the battery saver/power management system fuse circuit — if fuse blows again, there's still a short that needs to be found ($2-10 for fuses)
- Perform a wiggle test on the battery saver/power management system wiring harness while monitoring live data — see if the fault returns when you move the harness at different points ($0-104 diagnostic labor)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does P2D78 mean?
P2D78 stands for "Battery Charger Control Module B Processor Performance". P2D78 usually means battery Charger Control Module B Processor Performance.
Can you drive with P2D78?
Safe to drive — this is an informational or minor issue. Schedule diagnosis at your convenience.
How much does it cost to fix P2D78?
Repair costs for P2D78 typically range from $30 to $300, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($50-107 at shop, free at auto parts store for basic scan); Visually inspect the battery saver/power management system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $109 diagnostic fee at shop); Replace battery saver relay if testing confirms it has failed — use OEM quality, avoid the cheapest no-name aftermarket parts that fail in a year ($30-300).
Will P2D78 clear itself?
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