Standard EOBD

P0087 - Fuel Rail/System Pressure Too Low (Bank 1)

Q: What are the symptoms of fault code P0087?

Sensor signal is pegged at the lower voltage limit (0 V / ground) Check Engine Light (MIL) illuminated Possible drivability or power reduction Risk of failing an emissions inspection

Q: What causes fault code P0087?

Most likely: Short to ground on the signal wire or an internal short circuit within Fuel Rail/System Pressure Too Low (Bank 1) Bank 1 specific: Inspect wiring harness to cylinder bank 1 (firewall/right bank, exposed to exhaust manifold heat). Likely: Chafed or pinched wiring harness along the signal path to Fuel Rail/System Pressure Too Low (Bank 1) Possible: Internal mechanical wear or carbon deposits inside Fuel Rail/System Pressure Too Low (Bank 1) Rare: Defective internal output driver or reference circuit in the control module for Fuel Rail/System Pressure Too Low (Bank 1)

Q: How do you fix fault code P0087?

Cross-swap the component on Bank 1 with Bank 2 to rule out mechanical oil passages and internal timing wear. Measure signal wire resistance to chassis ground with connector unplugged (must exceed 10 kΩ; low reading confirms short to ground). Verify loaded supply voltage and harness terminal pins at Fuel Rail/System Pressure Too Low (Bank 1). Check circuit continuity and ground-side voltage drop (< 0.05 V) for Fuel Rail/System Pressure Too Low (Bank 1). Command device via scan-tool bidirectional control to verify mechanical operation and flyback spike. Mechanic tip: When an inductive relay/solenoid turns off, an inductive flyback spike (60 - 300 V) MUST appear on the scope. Absence of the spike indicates an open coil winding or an open module driver.

Related:Fuel Rail/System Pressure Too Low (Bank 1), Wiring harness and connectors, Control Module (ECM/PCM)

System

Powertrain (Engine & Gearbox)

Technical Description

The control module has detected a fault in the Fuel Rail/System Pressure Too Low (Bank 1) (P0087). The signal is below the lower threshold, typically from a short to ground or an internally shorted sensor. Affects cylinder bank 1 (bank 1 containing cylinder 1, firewall/right side).

Multimeter Test Points & Nominal Values

Test Point / Component	Measurement	Nominal Target Range	Test Condition
Fuel Rail/System Pressure Too Low (Bank 1) – Coil Resistance	Resistance (Ω)	20 - 120 Ω (relay) / 8 - 40 Ω (solenoid)	Device disconnected at 20°C
Fuel Rail/System Pressure Too Low (Bank 1) – Supply Voltage	Voltage (V)	11.8 - 14.4 V	Ignition ON, high side of load
Fuel Rail/System Pressure Too Low (Bank 1) – Control (Low Side) Rest / Active	Voltage (V)	Rest ≈ battery voltage / Active < 1.0 V	Module commanding device ON/OFF

Fuel Rail/System Pressure Too Low (Bank 1) – Coil ResistanceResistance (Ω)

Nominal Target:20 - 120 Ω (relay) / 8 - 40 Ω (solenoid)

Device disconnected at 20°C

Fuel Rail/System Pressure Too Low (Bank 1) – Supply VoltageVoltage (V)

Nominal Target:11.8 - 14.4 V

Ignition ON, high side of load

Fuel Rail/System Pressure Too Low (Bank 1) – Control (Low Side) Rest / ActiveVoltage (V)

Nominal Target:Rest ≈ battery voltage / Active < 1.0 V

Module commanding device ON/OFF

Oscilloscope Waveform Analysis

5 ms/div, 50 V/div

Scope the control side as the module commands the device. Switch-off must show a clear inductive spike (60 - 300 V); no spike means an open coil or a failed driver.