Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSJEEP2009GRAND CHEROKEE LAREDO, 3.0 M, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 9 (DTCS P0125 TO P0196 - GAS)P0172-FUEL SYSTEM 1/1 RICHDIAGNOSTIC TEST
2009 Jeep Grand Cherokee Laredo, 3.0 M, AWD
Diagnostic Test
2009 Jeep Grand Cherokee Laredo, 3.0 M, AWDSECTION Diagnostic Test
WARNING: This page is about a different variant/trim than selected.
- ACTIVE DTC NOTE: Check for contaminates that may have damaged an O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.
- Start the engine.
- Allow the engine to reach normal operating temperature.
- With a scan tool, select View DTCs.NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC Active or Pending at this time?
Yes
- Go to step 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
- CHECKING FUEL PRESSURE WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
- Turn the ignition off.
- Install a fuel pressure gauge to the fuel rail.
- Ignition on, engine not running.
- With the scan tool, actuate the ASD Fuel System test and observe the fuel pressure gauge.NOTE: Fuel pressure specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
- Turn the ignition off.
Choose a conclusion that best matches your fuel pressure reading.
Within Specification
- Go to step 3
Above Specification
- Replace the fuel filter/pressure regulator.
- Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
.CAUTION: Before Proceeding Stop All Actuations.
- O2 SENSOR OPERATION
- Start the engine.
- Allow the engine to reach normal operating temperature.NOTE: If one of the O2 Sensors Signal or Return circuit is shorted to ground or voltage, all the other O2 Sensor voltage readings will be affected.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.