This bulletin applies to 2016-2018 Mazda CX-9 vehicles built before November 10, 2017. Some customers may experience a lack of power with no warning lights and no related DTCs stored.
The concern most likely occurs when the fuel temperature is high and during situations where high power is required and could be caused when the learning value for the low pressure fuel pump exceeds a certain level and the PCM limits engine power to avoid a lack of fuel injection.
Even if the low pressure fuel pump has a problem, no DTCs may be stored.
To eliminate this concern, the PCM control logic has been modified not to limit engine power. After the modification, DTCs P0192:00 (high fuel pressure sensor circuit low input) or P0087:00 (high fuel pressure sensor circuit range/performance problem) are stored when the fuel injection amount is insufficient.
Inspect the low pressure fuel pump using the Mazda Modular Diagnostic system (M-MDS). If the low pressure fuel pump exhibits normal performance, reprogram the PCM without replacing the fuel pump.
If the low pressure fuel pump exhibits poor performance, replace it after reprogramming the PCM, following these steps:
1. Connect the M-MDS to the DLC-2;
2. Warm up the engine and leave it at idle with least electrical loads on it;
3. After the vehicle is identified, select the following items from the initialization screen of the M-MDS
- Select Datalogger
- Select Modules
- Select PCM
4. Select the following PID from the PID table:
- FP_DUTY (fuel pump control module control duty valve)
- FUEL_LO_T (fuel temperature inside the fuel supply line)
5. Mark a point on the graph for the PID data and verify if the point is located above the line - in the poor performance area or below the line in the normal performance area;
6. Re-boot the IDS to clear memory before reprogramming;
7. Using IDS 108.3 or later software, reprogram the PCM to the latest calibration.
