Diagnostic Test

WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

COMPARE THE ENGINE COOLANT TEMPERATURE TO THE OTHER TEMPERATURE SENSORS
NOTE:
Allow the engine to cool to ambient temperature before proceeding.
1. Turn the ignition on.
2. With the scan tool, compare the AAT, ECT and IAT Sensor values.
  Is the Engine Coolant Temperature Sensor value more than 15°C (59°F) difference compared to the other two sensor values?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
1. Refer to the recorded DTCs.
  Are there any other active component or circuit DTCs active or pending?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to 2.4L - DIAGNOSTIC CODE INDEX .
  No
  - Go To 3
CHECK FOR AN ACTIVE DTC
NOTE:
Review the vehicle repair history for any misfire condition repairs that have been performed. Diagnose and repair any misfire DTCs that are present before continuing with this procedure.
1. Turn the ignition on.
2. With the scan tool, read DTCs and record on the repair order. Copy DTC and Freeze Frame information to the repair order.
3. Start the engine and allow it idle.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
4. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
5. With the scan tool, read DTCs.
  Is the DTC active or pending?
  
  Yes
  - Go To 4
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
VISUALLY INSPECT THE ENGINE AND ACCESSORIES FOR WEAR, MISALIGNMENT, POOR CONNECTIONS, LEAKS, RESTRICTIONS, OR OTHER DAMAGE
NOTE:
Anything that affects the speed of the crankshaft can cause this DTC to set.
1. Inspect the engine for any of the following conditions:
  - Worn serpentine belt
  - Misalignment or binding water pump, P/S pump or A/C Compressor pulleys
  - Improper CKP, CMP, or MAP mounting
  - Poor connector/terminal to component connection for CKP Sensor, CMP Sensor, MAP Sensor, Fuel Injector, Ignition Coil, etc.
  - Vacuum leaks
  - Restriction in the air induction or exhaust system
  - Internal engine component malfunction
  NOTE:
  Rough Idle may occur and may not be caused by component failure. Any of the following conditions can be the cause:
  - Moisture on ignition system components
  - Insufficient fuel
  - Low quality fuel
  - Manual transmission bog
  - Towing overload
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 5
CHECK THE MAP SENSOR FOR PROPER OPERATION
1. Turn the ignition on.
2. With a scan tool, read the Barometric Pressure.
  NOTE:
  The Barometric Pressure should be approximately equal to the actual barometric pressure. If necessary, compare the Barometric Pressure value of this vehicle to the value of a known good vehicle of a similar make and model.
3. Turn the ignition off.
4. Connect a Vacuum Gauge to a Manifold Vacuum source.
  WARNING:
  When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
5. Start the engine.
6. Allow the engine to idle.
  NOTE:
  If engine will not idle, maintain a constant RPM above idle.
7. With the scan tool, read the MAP Sensor vacuum value.
  Is the scan tool reading for MAP vacuum within 1 inch of Hg of the Vacuum Gauge and is the Barometric Pressure reading of the vehicle approximately the same as actual Barometric Pressure?
  
  Yes
  - Go To 6
  No
  - Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. Replace the MAP Sensor if no problems were found with the connectors.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
CHECK THE FUEL DELIVERY SYSTEM FOR PROPER OPERATION
1. Perform the CHECKING THE FUEL DELIVERY SYSTEM test procedure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
  Were any problems found?
  
  Yes
  - Repair as necessary in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 7
INSPECT THE SPARK PLUGS AND IGNITION COILS FOR CRACKS, FOREIGN MATERIAL, OR OTHER DAMAGE
1. Turn the ignition off.
2. Remove the Spark Plugs.
3. Inspect the Spark Plugs and Ignition Coils/Ignition cables for the following conditions:
  - Cracks
  - Carbon Tracking
  - Foreign Material
  - Spark Plug gap size out of specifications
  - Loose or broken electrode
  - Fouling
  NOTE:
  Lightly tap the bottom of the spark plug on a solid surface. The electrode in the spark plug should not move.
  
  Were any of the above conditions present?
  
  Yes
  - Replace the Spark Plugs. If a Spark Plug was found to have carbon tracking or was fouled, verify that the Ignition Coil is not damaged.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 8
CHECK THE ENGINE MECHANICAL SYSTEMS FOR PROPER OPERATION
1. Check for any of the following conditions/mechanical problems:
  - ENGINE VACUUM - must be at least 13 inches in neutral
  - ENGINE VALVE TIMING - must be within specifications
  - ENGINE COMPRESSION - must be within specifications
  - ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
  - ENGINE PCV SYSTEM - must flow freely
  - TORQUE CONVERTER STALL SPEED - must be within specifications
  - POWER BRAKE BOOSTER - no internal vacuum leaks
  - FUEL - must be free of contamination
  - CYLINDER LEAKAGE TEST - must be within specifications
  Are there any engine mechanical problems?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - Go To 9
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all PCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL, 2.4L/3.2L .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST, 2.4L .