P0233 code definition
Fuel pump Secondary Circuit Intermittent
What the P0233 code means
P0233 is a generic OBD-II code that is triggered when the engine control module (ECM) detects that the secondary circuit to the fuel pump has an intermittent voltage when the fuel pump relay is turned on.
What causes the P0233 code?
The engine control module (ECM) detects low, or no voltage to the secondary fuel pump circuit when the fuel pump relay is turned on
The fuel pump relay may have a poor or intermittent contact internally on the secondary side of the relay
The inertia fuel shutoff switch (IFS) is not passing voltage through it intermittently to the pump
What are the symptoms of the P0233 code?
The Check Engine Light will be illuminated and the P0233 code set
The engine will not start from lack of fuel pump operation whenever the problem is occurring
The engine may run normally until the problem occurs, then it will lose power and the engine will stall
How does a mechanic diagnose the P0233 code?
Scans codes and documents the freeze frame data in order to verify the problem
Clears the DTC codes to verify whether the concern comes back
Checks the IFS connection for any loose or corroded pins
Checks the fuel pump feed fuse or fusible link to see if it has a good contact to vehicle power
Tests to see if voltage is getting to the fuel pump secondary circuit through the IFS and relay while wiggling connections and wiring for intermittent connections
Lightly taps on relay and IFS to see if connection is lost to power the secondary fuel pump supply voltage
Common mistakes when diagnosing the P0233 code
Follow these simple guidelines to prevent misdiagnosis:
Verify that the battery voltage is not low and connections are good, causing intermittent voltage drops in the electrical system
Check the electrical connections at the fuel pump relay and at the IFS for any loose connections on the secondary side
How serious is the P0233 code?
The fuel pump secondary circuit powers the fuel pump and can cause a no start or the engine to suddenly stall while driving
A low battery voltage can trigger the code if the voltage falls below a specified level
What repairs can fix the P0233 code?
Replacing the fuel pump relay if it is making intermittent connection on the secondary side of the relay
Replacing the IFS or relay if it shows signs of corrosion inside the connections, and cleaning or replacing the connector of all corrosion
Repairing a low battery voltage condition by replacing the battery, or repairing and cleaning the connections
Additional comments for consideration regarding the P0233 code
Code P0233 is triggered when the ECM detects intermittent low voltage in the secondary circuit to the fuel pump through the relay falling below a specified voltage. Some vehicles have an IFS and use a relay, so check both of these on those vehicles.
Need help with a P0233 code?
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