Fuel Pump Secondary Circuit Low
The PCM has detected a lower than normal voltage reading in the secondary, or feedback circuit of the fuel pump.
Code Set Parameters
The fuel pump is normally energized through the fuel pump relay, which is separate from the PCM. The feedback circuit supplies the PCM with voltage data regarding the primary circuit. When this data varies from a predetermined reference voltage, a code will be stored and a service engine soon lamp illuminated.
A trouble code P0230 may also accompany this code. If not, then a stored code and illuminated service engine soon lamp are normally the only symptoms.
Likely causes are a faulty fuel pump relay, a faulty PCM, the fuel pump safety interrupt switch has been activated (Ford), or an open circuit in the fuel pump wiring or connectors.
The fuel pump is often condemned in error when this code is exhibited.
- The fuel pump secondary circuit is the feedback circuit that provides input data (about the primary fuel pump circuit) to the PCM
- Any successful diagnosis of this code must include checking all related fuses and relays to ensure that the proper amount of voltage is present (typically this is a 5-volt reference signal)
A scanner or code reader, a digital volt ohmmeter, and access to a manufacturer’s wiring schematic will be necessary to successfully diagnose this code
Begin your diagnosis with a visual inspection of all wiring and connectors
- Repair or replace damaged, disconnected, shorted, or corroded wiring, connectors, and components as necessary
- Always retest the system after repairs are completed to ensure success.
If all system wiring, connectors, and components (Including fuses) appear to be in normal working order, connect the scanner (or code reader) to the diagnostic connector and record all stored codes and freeze frame data
- This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
- After the codes are cleared, operate the vehicle to see if the code returns
- If the code fails to immediately return, you may have an intermittent condition
- Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made.
Test voltage at the fuel pump connector to determine if there is sufficient power and ground when the ignition key is in the start position
- If the required voltage is present at the fuel pump, then suspect a shorted or faulty pump and repair as necessary
- If there is no voltage at the pump (or reduced voltage is present) then the problem is likely in the electrical wiring or connectors