The P2154: Fuel Injector Group ‘C’ Supply Voltage Circuit High refers to a condition where the voltage in the supply circuit for fuel injector group ‘C’ is higher than expected. This can lead to improper fuel delivery, causing engine performance issues such as misfires or inefficient fuel consumption. The problem could be due to faulty fuel injectors, wiring issues, or power supply faults.
P2154 – Quick Overview
Code | Information |
---|---|
Meaning | P2154: Fuel Injector Group ‘C’ Supply Voltage Circuit High |
Is it serious? | Yes, it can lead to improper fuel injection, misfires, and poor engine performance. |
Possible causes | – High voltage in the fuel injector group ‘C’ supply circuit – Faulty fuel injector group ‘C’ – Wiring issues or power supply problems |
How to diagnose? | – Measure voltage in the fuel injector group ‘C’ supply circuit – Test the fuel injector group ‘C’ – Inspect wiring and connections for faults |
P2154 Meaning
The P2154 code signals that the voltage supplied to fuel injector group ‘C’ is higher than the manufacturer’s specifications. This overvoltage can cause the injectors to function improperly, potentially leading to misfires, poor fuel economy, and rough engine performance. Common causes include faulty injectors, wiring issues, or a power supply fault.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for other related codes that could provide additional insight into the problem within the fuel system or power supply. | OBD-II Scanner |
Measure Voltage in the Supply Circuit | Use a multimeter to measure the voltage at the fuel injectors in group ‘C’. Compare the readings with the manufacturer’s specifications to confirm whether the voltage is higher than required. | Multimeter |
Test the Fuel Injectors | Use a diagnostic tool to test the fuel injectors in group ‘C’. Replace any injectors that are malfunctioning or not operating within the correct specifications. | Diagnostic Tool, Multimeter |
Inspect Wiring and Connectors | Visually inspect the wiring and connectors for fuel injector group ‘C’ for signs of damage, loose connections, or corrosion. Repair or replace any damaged wiring as necessary. | Flashlight, Multimeter |
Check Power Supply Components | Inspect the power supply components (fuse, relay, and ECU) that control the injectors. Ensure they are operating correctly and not causing an overvoltage situation. | Multimeter, Wiring Diagram |
Check for Electrical Faults | Perform continuity tests on the wiring to ensure there are no shorts or electrical faults that may be causing the high voltage in the supply circuit. | Multimeter, Wiring Diagram |
Clear the Code and Test Drive | After performing repairs or adjustments, clear the code using an OBD-II scanner and take the vehicle for a test drive to verify that the issue is resolved. | OBD-II Scanner |
Recheck for Codes | After the test drive, re-scan the vehicle to ensure the P2154 code has not returned. | OBD-II Scanner |

OBD-II scanner Buyer’s Guide
- Scanner features explained
- Different types of scanners
- Scanners for coding/odometer/ECU/checks
- Best picks + discount codes

Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)