Mazda Factory OBD-II DTC P0191 Code

DTC P0191	Fuel pressure sensor range/performance problem
DETECTION CONDITION	• The PCM monitors the input voltage from the fuel pressure sensor. If the voltages at PCM terminal 219 deviates from the threshold, the PCM determines that the there is a fuel pressure sensor problem.
POSSIBLE CAUSE	• Fuel pressure sensor malfunction • PCM malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED • Has the FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY • Verify related service repair information availability. • Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. • If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY CURRENT SIGNAL STATUS: IS CONCERN INTERMITTENT OR CONSTANT? • Connect the M-MDS to the DLC-2. • Clear the DTC from the PCM memory using the M-MDS. • Run the vehicle under the FREEZE FRAME DATA stored condition. • Is the same DTC present?	Yes	Go to the next step.
3		No	Intermittent concern exists. Perform the “INTERMITTENT CONCERNS TROUBLESHOOTING”.
4	INSPECT FUEL PRESSURE SENSOR • Inspect the fuel pressure sensor. • Is there any malfunction?	Yes	Replace the fuel pressure sensor, then go to the next step.
4		No	Go to the next step.
5	VERIFY THAT DTC P0191 TROUBLESHOOTING IS COMPLETED • Make sure to reconnect all disconnected connectors. • Clear the DTC from the PCM memory using the M-MDS. • Run the vehicle under the FREEZE FRAME DATA stored condition. • Is the same DTC present?	Yes	Replace the PCM, then go to the next step.
5		No	Go to the next step.
6	VERIFY AFTER REPAIR PROCEDURE • Perform the after repair procedure. • Are any DTCs present?	Yes	Go to the applicable DTC inspection.
6		No	DTC troubleshooting completed.