DTC P0091-00: Fuel Pressure Regulator Control Circuit Low Input: Notes

DTC P0091-00 PCM (SKYACTIV-G 2.5T) DETECTION CONDITION AND POSSIBLE CAUSE

DTC P0091-00	FUEL PRESSURE REGULATOR CONTROL CIRCUIT LOW INPUT
DETECTION CONDITION	When the PCM turns the spill valve control solenoid valve off but the spill valve control solenoid valve control circuit voltage is low for 5 s, the PCM determines that the spill valve control solenoid valve control circuit has a malfunction. MONITORING CONDITIONS The following conditions are met: Engine speed: 5, 700 RPM or less Battery voltage: 10.5 V or more Diagnostic support note This is a continuous monitor (CCM). The check engine light illuminates if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA/Snapshot data is available. DTC is stored in the PCM memory.
FAIL-SAFE FUNCTION	Stops high pressure fuel pump control Limits intake air amount
POSSIBLE CAUSE	High pressure fuel pump connector or terminals malfunction PCM connector or terminals malfunction Short to ground in wiring harness between high pressure fuel pump terminal B and PCM terminal 1EF Open circuit in wiring harness between the following terminals: High pressure fuel pump terminal A-PCM terminal 1EE High pressure fuel pump terminal B-PCM terminal 1EF Spill valve control solenoid valve (built-into high pressure fuel pump) malfunction PCM malfunction

DTC P0091-00

FUEL PRESSURE REGULATOR CONTROL CIRCUIT LOW INPUT

DETECTION CONDITION

When the PCM turns the spill valve control solenoid valve off but the spill valve control solenoid valve control circuit voltage is low for 5 s, the PCM determines that the spill valve control solenoid valve control circuit has a malfunction.

MONITORING CONDITIONS

The following conditions are met:
- Engine speed: 5, 700 RPM or less
  - Battery voltage: 10.5 V or more

Diagnostic support note

This is a continuous monitor (CCM).
The check engine light illuminates if the PCM detects the above malfunction condition during the first drive cycle.
FREEZE FRAME DATA/Snapshot data is available.
DTC is stored in the PCM memory.

FAIL-SAFE FUNCTION

POSSIBLE CAUSE

High pressure fuel pump connector or terminals malfunction
PCM connector or terminals malfunction
Short to ground in wiring harness between high pressure fuel pump terminal B and PCM terminal 1EF
Open circuit in wiring harness between the following terminals:
- High pressure fuel pump terminal A-PCM terminal 1EE
  - High pressure fuel pump terminal B-PCM terminal 1EF
Spill valve control solenoid valve (built-into high pressure fuel pump) malfunction
PCM malfunction

Fig 1: Fuel Pressure Regulator Control Circuit Diagram (Low Input)

Courtesy of MAZDA MOTORS CORP.

CAUTION:

Verify the malfunction symptom according to not only the PID value but also the symptom troubleshooting.

Related PIDs

PID DATA

ITEM (DEFINITION)	UNIT/CONDITION	DEFINITION	CONDITION/SPECIFICATION (REFERENCE)
FUEL_PRES	KPa {MPA}, mBar {BAR}, psi, in H20	Fuel pressure input from high fuel pressure sensor	Displays fuel pressure
	KPa {MPA}, mBar {BAR}, psi, in H20	Fuel pressure (absolute) input from high fuel pressure sensor	Displays fuel pressure (absolute)
	V	High fuel pressure sensor voltage	Ignition switched ON (engine off) Fuel pressure is approx. 16.91 MPa {172.4 kgf/cm ² , 2453 psi}: Approx. 2.91 V Idle (after warm up) Fuel pressure is 3.44-3.95 MPa {35.1-40.2 kgf/cm ² , 499-572 psi}: 0.98-1.05 V (ECT is 90 °C {194 °F})