What this code means
P0087 may mean the direct-injection fuel rail pressure is lower than the vehicle expects under certain operating conditions.
What the vehicle may do
- The vehicle may have a hard start, stumble, low power, rough running, or a warning light.
- The fault can be intermittent and may only appear when similar operating conditions are reproduced.
Possible fault areas
- Possible low-pressure fuel supply concerns may be involved.
- Possible high-pressure fuel pump or spill valve concerns may be involved.
- Possible fuel rail pressure sensor signal or connector concerns may be involved.
- Possible fuel leaks may be involved.
- Related fuel, ignition, misfire, or control faults can affect the diagnostic direction.
Diagnostic path
Opening context
On this Accord, P0087 means the direct-injection fuel rail pressure is being seen as too low. The car may have a hard start, stumble, low power, rough running, or set the light when the operating conditions line up. Broadly, this can involve a possible low-pressure fuel supply issue, a high-pressure pump or spill valve issue, a fuel rail pressure sensor signal issue, leaks, wiring or terminal problems, or related fuel and ignition faults that are setting at the same time. Before chasing P0087 by itself, start with the basic system checks and follow a structured diagnostic approach.
Before testing P0087
First, capture the stored operating data and any on-board snapshots with the HDS. If the vehicle ran out of fuel and stalled before this code set, refuel it, clear the code, and recheck it. Also look for any fuel leak before continuing, because a leak can set this code. And if other related codes are stored at the same time, especially fuel pressure sensor, injector, misfire, ignition, air-fuel, or control-related faults, diagnose those first, then come back and recheck P0087.
Verify the fault at idle
Start by trying to verify the problem at idle. With the HDS, clear the code, start the engine, and warm it up by holding engine speed at 3,000 rpm with no load, automatic in P or N, manual in neutral, until the radiator fan comes on. Then let it idle and run the DI FUEL PRESSURE TEST from the inspection menu. If that test result is OK, move to a test drive under the captured conditions. If it is not OK, go straight into the spill valve operation check.
Verify it on the road if the idle test passes
If the idle check passes, test-drive the vehicle for several minutes while matching the captured conditions as closely as possible: engine speed, vehicle speed, MAP, throttle position, accelerator position, coolant temperature, and intake air temperature. Then check for pending or confirmed P0087 with the HDS. If P0087 returns, the failure is duplicated and you continue to the spill valve check. If P0087 does not return, treat it as intermittent. At that point, the system is OK at this time. Test PGM-FI main relay 2, and if the relay checks OK, inspect for poor connections or loose terminals at the fuel rail pressure sensor, the high pressure fuel pump, and the PCM.
Check high-pressure pump spill valve operation
With the engine running at idle, listen and feel for noise or vibration from the spill valve on the high pressure fuel pump. If the pump is operating, you should hear some noise from that spill valve. If noise or vibration is present, continue to the first fuel rail pressure sensor check. If there is no noise or vibration, the diagnostic path supports replacing the high pressure fuel pump, then verifying the repair.
Fuel rail pressure sensor check one
Next, shut the vehicle off and remove PGM-FI main relay 2 from the under-dash fuse and relay box. Start the engine and let it idle until it stalls. After it stalls, crank the engine several times. Then watch FUEL PRESSURE CONVERTED FROM PF SENSOR on the HDS. It is normal if the value shows several hundred kPa before this check, but during this check the value should change to about 0 kPa. If it does, continue to the second sensor comparison check. If it does not, the diagnostic path supports replacing the fuel rail, meaning the fuel rail pressure sensor, then verifying the repair.
Fuel rail pressure sensor check two
Reinstall PGM-FI main relay 2, start the engine, and warm it up again at 3,000 rpm with no load, automatic in P or N, manual in neutral, until the radiator fan comes on. Then let it idle. On an automatic, shift to D while holding the brake firmly, then press the accelerator pedal. Do not move the shift lever or take your foot off the brake while raising engine speed. On a manual, snap the throttle several times, and use Line Graph Setup mode on the HDS to compare the values. Compare FUEL PRESSURE CONVERTED FROM PF SENSOR to FUEL PRESSURE DIRECT INJECTION SYSTEM. If both values are almost the same, the fuel rail pressure sensor is OK and you move to the low-pressure side fuel pressure check. If they are not almost the same, the diagnostic path supports replacing the fuel rail, meaning the fuel rail pressure sensor, then verifying the repair.
Check the low-pressure side
Now check fuel pressure on the low-pressure side. If the fuel pressure is OK, the low-pressure side is considered OK and you move on to the high pressure fuel pump visual check. If the fuel pressure is not OK, check the fuel pump, fuel pressure regulator, fuel filter, and fuel lines, then verify the repair.
Inspect the high-pressure pump drive parts
If the low-pressure side passes, remove the high pressure fuel pump and visually inspect the cam that drives the pump and the pump roller for wear or damage. If those parts are OK, the diagnostic path supports replacing the high pressure fuel pump, then verifying the repair. If the parts are not OK, check the cam and roller damage, then verify the repair.
Verify the repair
Keep verification separate from the testing steps. Turn the ignition on, reset the PCM with the HDS, and perform the PCM idle learn procedure. Then run the DI FUEL PRESSURE TEST again and check for pending or confirmed codes with the HDS. If P0087 is still indicated, check for poor connections or loose terminals at the fuel rail pressure sensor, the fuel rail pressure control valve, and the PCM, then pause, recheck the earlier diagnostic path, and avoid guessing. If P0087 is not indicated, troubleshooting for this code is complete. If any other pending or confirmed codes remain, diagnose those separately.
Closing takeaway
The takeaway on P0087 is to prove whether the low rail pressure is real, sensor-related, supply-related, or a high-pressure pump control problem before calling the part. Capture the conditions, duplicate the fault, compare the pressure signals, confirm low-side supply, inspect the pump drive, and then verify the code stays gone. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis often comes down to proving whether the pressure loss is real, sensor-related, supply-related, or tied to high-pressure pump control before making a repair decision.
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