OBD-II trouble code
P2285: Injector Control Pressure Sensor Circuit Low
The signal voltage has fallen below its valid window. This is the member of the family that can stop the engine starting outright, because the module withholds injection until it sees enough pressure to justify it.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $20 – $600
- DIY difficulty
- Intermediate DIY
Browse every code in P2200–P229F, or start from the full code library.
What does P2285 mean?
The injector control pressure sensor returns a voltage that rises with pressure, occupying a narrow band well inside the five-volt supply it is given. P2285 sets when that returned voltage drops beneath the bottom of the band — below roughly a fifth of a volt on most applications — which is lower than a working sensor produces even with the engine stopped and no pressure in the rails at all.
What separates this member from the rest of the family is that it can be the direct cause of a no-start rather than a passenger alongside one. Hydraulically actuated injectors need a minimum oil pressure before they will open at all, and the module knows it: it waits for the sensor to confirm a starting threshold in the region of 500 psi before it will command any injection. If the sensor reports less than that, the module simply does not fire the injectors. The pump may well be building perfectly good pressure; the engine cranks and cranks and never catches because the only witness the module has is lying to it. An engine that eventually starts after several long cranking attempts, or that starts and immediately dies, fits this pattern closely.
Electrically, a reading below the valid floor means one of three things: the signal line is shorted to ground, it has lost its supply, or the sensor has failed to a low output. The short-to-ground case includes the oil-contamination failure this family is known for, where oil in the connector bridges the signal terminal to the shield or the ground pin.
Before condemning the sensor, check the company it keeps. The five-volt reference feeding it is shared with other sensors on most of these engines, and a single shorted sensor elsewhere can drag that reference down for everything on the circuit. Several unrelated low-side codes appearing at once — pressure, position and temperature sensors all complaining together — is the signature of a collapsed reference, and replacing the injection pressure sensor in that situation fixes nothing.
Common causes
- Signal wire shorted to ground or to chassis through damaged insulation
- Oil in the connector bridging the signal terminal to ground
- Sensor failed internally to a permanently low output
- Open five-volt supply wire to the sensor
- Shared reference circuit pulled down by a different shorted sensor
- Corroded or backed-out terminal in the sensor plug
- Harness crushed against a bracket where it crosses the engine
- Poor repair splice that has corroded and lost continuity
- Water intrusion into the connector after pressure washing the engine bay
Symptoms
- Extended cranking, or a no-start that resolves after several attempts
- Engine starts and immediately stalls
- Check engine light with a reported pressure of zero at all times
- Loss of power once running, or a persistent rough idle
- Hard starting that is worse in cold weather
- Several unrelated sensor codes appearing in the same session
- Scan tool pressure reading that never changes regardless of throttle
Diagnostic steps
- 1.Read the reported pressure with the key on and the engine off. A healthy sensor produces a small but non-zero voltage here; a flat zero on the scan tool is consistent with the fault the code describes.
- 2.Look at every other code in memory before testing. Multiple low-side sensor codes at once point at a shared reference problem rather than at this sensor.
- 3.Unplug the sensor and check whether the reported value swings to its opposite extreme. A reading that does not move with the plug removed means the fault is in the wiring, not the sensor.
- 4.Measure the five-volt supply at the connector with the key on. No supply moves the search back toward the module and the reference circuit.
- 5.Check the signal terminal for continuity to ground with the sensor disconnected. Continuity there confirms a short and rules the sensor out.
- 6.Inspect the connector cavity for oil or moisture, which can bridge terminals and mimic a wiring short exactly.
- 7.If a no-start is the complaint, confirm during cranking whether the module is commanding injection at all. Silence from the injectors with healthy cranking speed points squarely here.
- 8.Follow the harness across the engine looking for a crush point at any bracket, clamp or heat shield it passes.
- 9.Repair or replace the pigtail rather than splicing into the existing wire wherever oil contamination is present.
Repair cost
$20 – $600
A backed-out terminal or a corroded pin can be fixed for the price of a terminal kit, around $20. A pigtail is $20 to $60. The sensor itself is $45 to $260 plus half an hour to three hours of labour depending on access. Tracing and repairing a shorted section of harness runs $120 to $400 because the labour is in the finding rather than the fixing. Diagnostic time is typically $110 to $190.
Estimate your repair
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Open the Repair Cost Estimator with injector control pressure sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.