What this code means
P2623 means the PCM may be seeing high-pressure fuel pump spill valve behavior that does not match the command it expects.
What the vehicle may do
- The engine may crank longer than normal or may be hard to start.
- The vehicle can run poorly, hesitate, or feel down on power.
- The warning light may be the only obvious symptom.
Possible fault areas
- Possible pump control power or relay-related circuit faults.
- Possible HPUMP control circuit wiring or connector issues.
- Possible high-pressure fuel pump fuel control solenoid concern.
- Possible PCM-side fault area after the other inspections test normal.
Diagnostic path
Code overview and starting point
On this Accord Hybrid, P2623 is a high-pressure fuel pump spill valve malfunction. In plain terms, the PCM may be seeing pump behavior that does not match the command it expects. The vehicle may have a hard start, poor running, hesitation, reduced power, or just a warning light. The broad areas to think about are pump control power and ground paths, the HPUMP control circuits, the fuel control solenoid inside the high-pressure pump, and, only after the other checks pass, the PCM side of the circuit. Start with the basic system checks and follow a structured diagnostic approach. If other injector-circuit codes are present with P2623, use that as context for the branch that includes the injector relay power and control feed checks first. If P2623 is the only relevant code, the path moves into the high-pressure pump control circuit and solenoid checks.
Confirm the fault under the right conditions
For confirmation, enter maintenance mode and start the engine. If the engine does not start, crank the engine for 20 seconds. This gives the PCM a chance to run the command-versus-response check that sets this fault.
Branch the diagnosis without chasing the wrong path
Now decide which path applies. When P2623 is stored along with injector-circuit faults, include the injector relay feed and control circuit inspection before moving on. When those injector-circuit faults are not part of the failure, skip that branch and go directly to the HPUMP circuit and fuel control solenoid checks. The logic is simple: prove the shared power and command paths first when the fault pattern points there, then test the pump-control side.
Injector relay feed and control circuit checks, when that branch applies
If the injector-circuit branch applies, prepare the PCM safely before unplugging it. Jump the SCS line with the HDS, then wait more than 1 minute before disconnecting the PCM connector. Disconnect the injector relay and PCM connector A, the 72-pin connector. Then inspect the disconnected injector relay socket and PCM connector A terminals according to the circuit table. The normal readings listed for the OFF state are 12 V battery voltage on the +B_INJ and +B_IGP power checks. The FI_MAIN_RLY_CL- open-wire check should be less than 1 Ω, and both INJ_RLY_OUT open-wire checks should also be less than 1 Ω. If this inspection is abnormal, treat it as a circuit problem. If the power supply portion is abnormal, continue with the additional power supply inspection to locate the failure.
HPUMP_H and HPUMP_L circuit checks
Next, check the HPUMP_H and HPUMP_L circuits. Again, before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Disconnect the high-pressure fuel pump 2-pin connector and PCM connector B, the 101-pin connector. Then run the listed checks between the disconnected pump connector and PCM connector B. The normal open-wire readings for HPUMP_H and HPUMP_L are less than 1 Ω with the circuit OFF. The normal short-to-ground readings are more than 1 MΩ with the circuit OFF. With the circuit ON, the HPUMP_H and HPUMP_L short-to-power checks should show not shorted. For the HPUMP_H and HPUMP_L shorted-circuit inspection, use the proper open-or-shorted-wire test method for the shorted circuit, then continue the inspection based on the condition you are chasing. If any of these checks are abnormal, there is a problem in that circuit.
Fuel control solenoid inspection
After the external circuit checks, inspect the fuel control solenoid circuit. This solenoid inspection can be done before the other individual inspections because it includes all of those items, but only when the external circuit is normal. If that combined test fails, continue with the individual inspections to find which item failed. Before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Then disconnect PCM connector B, the 101-pin connector, and inspect the disconnected connector terminals according to the solenoid table. The normal solenoid internal circuit reading, with the circuit OFF, is less than 1 Ω. If that result is abnormal, the problem is with the high-pressure fuel pump.
PCM conclusion
Only after the other inspection items have shown normal results do you move the conclusion to the PCM. At that point, the remaining fault area is the PCM itself. Do not jump to that conclusion before the power feeds, control circuits, HPUMP_H and HPUMP_L wiring, and solenoid circuit have all been proven normal.
Takeaway
The key with P2623 is to separate a command problem from a response problem. Use the related fault pattern to choose the right branch, prove the supply and control circuits first, then test the pump solenoid circuit, and leave the PCM conclusion for last. For more diagnostic training, visit stepdiagnostics.com.
Final check
P2623 is often best approached as a command-versus-response diagnosis: prove the supporting circuits first, then the pump solenoid circuit, and consider the PCM only after the rest of the path checks.
For more guided automotive diagnostics, visit STEP Diagnostics.
