DTC U1418, Checking for Intermittent Condition, System Checks, Component Checks: Diagnosis Jeep Compass I

Diagnostic Test

1. ACTIVE DTC NOTE: For vehicle communication problems, use the scan tool to refer to the Network Review Screen. The screen depicts a high level view of the vehicle network. Fault and problem areas appear in red. Selecting any of the network components allows access to the source of the problem. Ignition on, engine not running. With a scan tool, select View DTCs. Is the status Active for this DTC? Yes Go To 2 . No Refer to the «*CHECKING FOR AN INTERMITTENT CONDITION»(ref-304395-S28853819902008110700000) Diagnostic Procedure. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
2. ABS MODULE IS ACTIVE ON THE CAN C BUS Using the Network Review Screen on the scan tool, verify that the ABS Module is active on the bus. Is the ABS Module active on the bus? Yes Go To 3 . No Refer to «DIAGNOSIS AND TESTING»(ref-304334-S10935475992008110700000) for No Response diagnostic procedures. Perform «BODY VERIFICATION TEST - VER 1»(ref-304334-S29410035802008110700000) .
3. DTCS STORED OR ACTIVE IN THE ABS MODULE With the scan tool, select View DTCs in the ABS Module. Are any DTCs active or stored in the ABS Module? Yes Refer to «ABS ELECTRICAL DIAGNOSTICS»(ref-304336-S35363016692008110700000) and perform the appropriate diagnostic procedure. Perform «ABS VERIFICATION TEST»(ref-304336-S24283575812008110700000) . No Go to 4 .
4. ACTIVE DTCS IN THE TIPM With the scan tool, select ECU View and select the TIPM. With the scan tool, select View DTCs in the TIPM. Are any ABS related DTCs active or stored in the TIPM? Yes Replace the ABS Module in accordance with the Service Information Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace and program the Powertrain Control Module per Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

1. INTERMITTENT DTC 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 can result in personal injury or death. The conditions necessary to set this DTC are not present at this time. Review the scan tool environmental data. If possible, try to duplicate the conditions under which the DTC set. If applicable, actuate the component with the scan tool. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors. Look for the data to change, the actuation to be interrupted, or for the DTC to reset during the wiggle test. Refer to any Technical Service Bulletins (TSBs) that may apply. Turn the ignition off. Visually inspect the related wire harness. Disconnect all the related harness connectors. Look for any chafed, pierced, pinched, partially broken wires and broken, bent, pushed out, or corroded terminals. Perform a voltage drop test on the related circuits between the suspected component and the PCM. Inspect and clean all PCM, engine, and chassis grounds that are related to the most current DTC. If numerous trouble codes were set, use a schematic and inspect any common ground or supply circuits. For intermittent Misfire DTCs check for restrictions in the Intake and Exhaust system, proper installation of Sensors, vacuum leaks, and binding components that are run by the accessory drive belt. Use the scan tool to perform a System Test if one applies to the component. A co-pilot, data recorder, and/or lab scope should be used to help diagnose intermittent conditions. Were any problems found during the above inspections? Yes Perform the necessary repairs. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Test Complete.

Scheme 585

1. ENGINE COOLANT TEMPERATURE SENSOR WIRING OR CONNECTORS NOTE: Diagnose and repair any ECT circuit DTCs before proceeding with this test. NOTE: Allow the engine to cool to ambient temperature before proceeding. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Coolant Temperature sensor(s) and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Turn the ignition on. Monitor the scan tool data relative to the sensor(s) and wiggle test the wiring and connectors. Look for the data to change or for a DTC to set during the wiggle test. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. ENGINE COOLANT LEVEL AND CONDITION WARNING: Make sure the engine cooling system is cool before removing the pressure cap or any hose. The cooling system is pressurized when hot. Failure to follow these instructions can result in personal injury including extreme burns, scalding, or death. Check the engine coolant level and the condition of the engine coolant. Refer to the appropriate Service Information. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 3 .
3. THERMOSTAT WARNING: Make sure the engine cooling system is cool before removing the pressure cap or any hose. The cooling system is pressurized when hot. Failure to follow these instructions can result in personal injury including extreme burns, scalding, or death. Using the appropriate service information, determine the proper opening temperature of the thermostat. With the scan tool, read the Engine Coolant Temperature Sensor value for each sensor. If the engine was allowed to cool completely, the value should be approximately equal to the ambient temperature. Monitor the sensor values on the scan tool. Start the engine. 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 can result in personal injury or death. NOTE: Each thermostat should open at the temperature specified in the Service Information. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 4 .
4. ENGINE COOLANT TEMPERATURE SENSOR NOTE: Allow the engine to cool to ambient temperature before proceeding. WARNING: Make sure the engine cooling system is cool before removing the pressure cap or any hose. The cooling system is pressurized when hot. Failure to follow these instructions can result in personal injury including extreme burns, scalding, or death. With the scan tool, read the Engine Coolant Temperature Sensor value for each sensor. If the engine was allowed to cool completely, the value should be approximately equal to the ambient temperature. Monitor each sensor value on the scan tool and the actual coolant temperature with a thermometer. Start the engine. 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 can result in personal injury or death. NOTE: The sensor value transition should be smooth as the engine reaches operating temperature. The thermometer reading and the coolant temperature values on the scan tool should remain relatively close. Were any problems found? Yes Go to step 5 . No Test complete.
5. ECT SIGNAL CIRCUIT HIGH RESISTANCE NOTE: Perform this procedure for the sensor where erratic sensor values were detected in the previous test step. Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the ECT Signal circuit at the Engine Coolant Temperature Sensor harness connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 6 . No Repair the ECT Signal circuit for excessive resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
6. SENSOR GROUND CIRCUIT HIGH RESISTANCE Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the Sensor Ground circuit at the Engine Coolant Temperature Sensor harness connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 7 . No Repair the Sensor Ground circuit for excessive resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
7. ENGINE COOLANT TEMPERATURE SENSOR Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Coolant Temperature Sensor and the Powertrain Control Module (PCM). Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Refer to any Technical Service Bulletins that may apply. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace the Engine Coolant Temperature Sensor. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

1. CHECKING THE ENGINE MECHANICAL SYSTEM Turn the ignition off. Check for any of the following conditions/mechanical problems: - AIR INDUCTION SYSTEM - must be free from leaks and restrictions - 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 from leaks and restrictions - ENGINE OIL - must be clean, at the proper level, free from contamination or fuel - 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 - FUEL INJECTOR - plugged or restricted injector(s); control wire not connected to the correct injector - CAM LOBES - must not be worn excessively - CYLINDER LEAKAGE TEST - must be within specifications - VALVE SPRINGS - cannot be weak or broken Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Test Complete.

1. CHECKING THE EXHAUST SYSTEM FOR LEAKS Turn the ignition off. Raise the vehicle in accordance with the Service Information. WARNING: The normal operating temperature of the exhaust system is very high. Never work around or attempt to service any part of the exhaust system until it has cooled. Special care should be taken when working near the catalytic converter. The temperature of the converter rises to a high level after a short period of engine operating time Connect Exhaust Cone #8404-EC to Air Pressure Regulator (with hose) #W-18-MIL-1146AS. CAUTION: The air pressure must not exceed 27.6 KPA (4 psi), otherwise engine damage can occur. Attach shop air to the air pressure regulator. Adjust the Air Pressure Regulator to 27.6 KPA (4 psi) Insert the exhaust cone into the vehicle tail pipe. If equipped with dual exhaust, plug the other exhaust pipe. Apply Mopar® Air Leak Detector (or equivalent) to the following areas: - All welded joints from 6 inches rearward of the downstream O2 sensor forward - O2 sensor seal points - O2 sensor boss welds - Flange/joint connection(s) - Exhaust manifold to cylinder head connection(s) - EGR solenoid gasket base and tube seal points (if equipped) Watch for the leak detector solution water to bubble. Use the following definitions to help determine if system or component repair/replacement is necessary: Type 1 Leak is defined as a leak where very small foam like bubbles approximately 1 mm (0.04 in.) or less appear. Any Type 1 or greater leaks found in welded joints, O2 sensor seal points or O2 sensor boss welds must be repaired or the component must be replaced. Type 2 Leak is defined as a leak where larger, pea size bubbles, approximately 8mm (0.31 in.) or greater appear. Any Type 2 or greater leaks found in flange or joint connections, exhaust manifold to cylinder head connections, or EGR gasket and tube seal points must be repaired or the components must be replaced Leak Location Repair required if results at 4 psi reveal bubble size: Welded joints Type 1: 1 mm (0.04 in.) or greater O2 Sensor seal points Type 1: 1 mm (0.04 in.) or greater O2 Sensor boss welds Type 1: 1 mm (0.04 in.) or greater Flange / joint connections Type 2: 8 mm (0.31 in.) or greater Exhaust Manifold to cylinder head connections Type 2: 8 mm (0.31 in.) or greater EGR gasket and tube seal points Type 2: 8 mm (0.31 in.) or greater If a leak is found that matches the above definition, repair or replace the component as necessary. Once the repair is complete, repeat the procedure to verify that all leaks have been repaired. Were any exhaust leaks found? Yes Repair or replace the leaking exhaust parts as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Test complete.

1. CHECKING THE FUEL PUMP OPERATION Turn the ignition on. NOTE: Diagnose and repair any fuel pump control circuit or relay DTCs before continuing with this test. With a scan tool, actuate the fuel pump control to ON (100%). NOTE: It may be necessary to use a mechanics stethoscope in the next step. Listen for fuel pump operation at the fuel tank. The fuel pump should operate smoothly, without excessive noise. If necessary, compare to a known good vehicle of similar year, make, and model. NOTE: If the pump has excessive noise or grinding, the pump should be replaced. CAUTION: Stop all actuation tests before continuing. Is the fuel pump operating when actuated? Yes Go to step 2 . No Go to step 7 .
2. CHECKING THE FUEL PRESSURE Turn the ignition off. 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 personal injury or death. Install a fuel pressure gauge on the fuel rail. Turn the ignition on. With the scan tool, actuate the fuel pump relay control. Observe the fuel pressure gauge. NOTE: The fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). CAUTION: Stop all actuation tests before continuing. Select the conclusion that best matches the result of the test: Fuel pressure is within the stated specification Test complete. Fuel pressure is below the stated specification Go to step 3 . Fuel pressure is above the stated specification Replace the fuel filter/pressure regulator. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
3. RESTRICTED FUEL SUPPLY LINE Turn the ignition off. 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 personal injury or death. Raise vehicle on hoist, and disconnect the fuel pressure line at the fuel pump module. Install special 5/16 fuel line adapter tool #6539 between disconnected fuel line and the fuel pump module. Attach a fuel pressure test gauge to the T fitting on tool #6539. Turn the ignition on. With the scan tool, actuate the fuel pump relay control. Observe the fuel pressure gauge. NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). CAUTION: Stop all actuation tests before proceeding. Is the fuel pressure within specification? Yes Repair or replace fuel supply line as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 4 .
4. SADDLE FUEL TANK Is the vehicle equipped with a saddle type fuel tank? Yes Go to step 5 . No Go to step 6 .
5. FUEL TANK SIPHON HOSE OR FUEL LINE RESTRICTED OR DAMAGED Turn the ignition off. 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 personal injury or death. Gain access to the fuel pump module and the fuel tank module. Inspect the fuel line and siphon hose between the fuel pump module and the fuel tank module. Look for disconnected or damaged lines and hoses. Inspect the fuel pressure regulator for damage or a condition that might cause a fuel flow problem. Make sure that it is seated in the module properly. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 6 .
6. FUEL PUMP INLET STRAINER Turn the ignition off. 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 personal injury or death. Remove the fuel pump module and inspect the fuel inlet strainer for damage or a condition that might cause a fuel flow problem. Were any problems found? Yes Replace the Fuel Pump Inlet Strainer. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace the Fuel Pump Module. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
7. FUEL PUMP GROUND CIRCUIT OPEN OR HIGH RESISTANCE Turn the ignition off. Disconnect the Fuel Pump Module harness connector. Using a 12 volt test light connected to 12 volts, check the Fuel Pump Motor Ground circuit at the Fuel Pump Module harness connector. NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery. Is the test light illuminated and bright? Yes Replace the Fuel Pump Module in accordance with the Service information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Repair the Fuel Pump Ground circuit for an open circuit or high resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

Scheme 586

1. IGNITION COIL WIRING OR CONNECTORS NOTE: Diagnose and repair any ignition coil, CMP sensor, or CKP sensor DTCs before proceeding with this test. Turn the ignition off. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ignition Coil for the cylinder being tested and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. NOTE: If the vehicle is not equipped with the coil on plug ignition system, check the resistance of the ignition wire(s) before checking the cylinder with a spark tester. The resistance should be below 10k ohms. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. IGNITION COIL OPERATION NOTE: Inspect the ignition coil for damage, carbon tracking on the coil or a damaged spark plug insulator boot. If a problem is found, replace the ignition coil. NOTE: 6.1L coils must have a spark tester installed on both sides of the coil during the following test. During the test, each side of the coil should output a crisp blue spark that is able to jump the gap of the spark tester. NOTE: On the 2.7 and 3.5 engines, cylinders 1, 3 and 5, it is necessary to remove the upper intake manifold to access the ignition coils. Once the ignition coil has been removed, the intake must be installed in order to crank the engine. Move the ignition coil harness connector through the slots in the upper intake and then connect the coil to the harness connector. Secure the upper intake to the lower intake in accordance with the Service Information. Turn the ignition off. If the vehicle is equipped with coil on plug ignition system, remove the ignition coil for the cylinder being tested. Disconnect the fuel injector harness connector for the cylinder being tested. For coil on plug ignition systems, install a spark tester(s) on the ignition coil, otherwise install the spark tester to the ignition wire. While cranking the engine observe the spark coming from the spark tester. NOTE: A crisp blue spark that jumps the gap of the spark tester should be generated. Is good spark present? Yes Go to step 7 . No Go to step 3 .
3. MAIN/ASD RELAY OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE Turn the ignition off. Disconnect the Ignition Coil harness connector. Turn the ignition on. With the scan tool, actuate the Main/ASD Relay to on. Using a 12 volt test light connected to ground, check the Main/ASD Relay output circuit in the ignition coil harness connector. NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery. Is the test light illuminated and bright during the actuation? Yes Go to step 4 . No Repair the Main/ASD Relay output circuit for an open circuit or high resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
4. IGNITION COIL 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 can result in personal injury or death. Using a 12 volt test light connected to 12 volts, check the Ignition Coil control circuit for the cylinder being tested in the Ignition Coil harness connector. Crank the engine for 5 seconds. NOTE: The test light should blink each time the circuit is activated by the PCM. Does the test light blink each time the circuit is activated by the PCM? Yes Replace the Ignition Coil in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 5 .
5. IGNITION COIL CONTROL CIRCUIT OPEN OR HIGH RESISTANCE CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis. Measure the resistance of the Ignition Coil control circuit for the cylinder being tested between the Ignition Coil harness connector and the appropriate terminal of special tool #8815. Is the resistance below 5.0 ohms? Yes Go to step 6 . No Repair the Ignition Coil control circuit for an open circuit or high resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
6. POWERTRAIN CONTROL MODULE (PCM) Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ignition Coil for the cylinder being tested and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Refer to any Technical Service Bulletins that may apply. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
7. SPARK PLUG(S) Turn the ignition off. Remove the spark plug. NOTE: Vehicles equipped with 5.7L or 6.1L engines must have both spark plugs (per cylinder) removed and inspected to ensure proper operation. Inspect the spark plug for any of the following conditions: - Cracks or damage - Carbon tracking - Foreign material - Gap not within specification - Loose or broken electrode NOTE: Lightly tap the bottom of the spark plug on a solid surface. The electrode in the spark plug should not move. Were any problems found? Yes Replace the spark plug. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Test Complete.

Scheme 587

1. MAP SENSOR WIRING OR CONNECTORS NOTE: Diagnose and repair any MAP Sensor circuit DTCs before proceeding with this test. NOTE: Diagnose and repair any sensor supply or system voltage DTCs before proceeding with this test. Turn the ignition off. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Turn the ignition on. Monitor the scan tool data relative to the sensor and wiggle test the wiring and connectors. Look for the data to change or for a DTC to set during the wiggle test. If necessary, check each sensor circuit for high resistance or a shorted condition. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. MAP VACUUM/BAROMETRIC PRESSURE 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 the tested vehicle to the value of a known good vehicle of a similar make and model. Connect a vacuum gauge to a manifold vacuum source. Start the engine. NOTE: If engine will not idle, maintain a constant RPM above 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 can result in personal injury or death. With the scan tool, read the MAP Sensor vacuum. NOTE: The scan tool reading for MAP vacuum should be within 1" of the vacuum gauge reading. Were any problems found? Yes Go to step 4 . No Go to step 3 .
3. MAP SENSOR VOLTAGE With the scan tool, monitor the MAP Sensor signal voltage. With the engine idling in neutral or park, snap the throttle. NOTE: The MAP Sensor signal voltage should change from below 2.0 volts at idle to above 3.5 volts at wide open throttle. Were any problems found? Yes Go to step 4 . No Test complete.
4. (F856) 5 VOLT SUPPLY CIRCUIT HIGH RESISTANCE Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the (F856) 5 Volt Supply circuit at the MAP Sensor harness connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 5 . No Repair the (F856) 5 Volt Supply circuit for excessive resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
5. (K1) MAP SIGNAL CIRCUIT HIGH RESISTANCE Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the (K1) MAP Signal circuit at the MAP Sensor harness connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 6 . No Repair the (K1) MAP Signal circuit for excessive resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
6. (K900) SENSOR GROUND CIRCUIT HIGH RESISTANCE Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the (K900) Sensor Ground circuit at the MAP Sensor harness connector and by probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 7 . No Repair the (K900) Sensor Ground circuit for excessive resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
7. MAP SENSOR Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor and the Powertrain Control Module (PCM). Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Refer to any Technical Service Bulletins that may apply. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace the MAP Sensor. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

Scheme 588

1. OXYGEN SENSOR, WIRING, OR CONNECTORS NOTE: Diagnose and repair any O2 sensor or rationality DTCs before proceeding with this test. NOTE: When performing this procedure as part of another diagnostic process, it may be necessary to repeat this test for all of the oxygen sensors on the vehicle. Turn the ignition off. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Oxygen sensor and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Turn the ignition on. Monitor the scan tool data relative to the sensor and wiggle test the wiring and connectors. Look for the data to change or for a DTC to set during the wiggle test. If necessary, check each sensor circuit for high resistance or a shorted condition. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. OXYGEN SENSOR VOLTAGE Start the engine and allow it to reach normal operating temperature. 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 can result in personal injury or death. With a scan tool, monitor all O2 Sensor voltage readings. Is the voltage switching between 2.5 and 3.4 volts for all O2 sensors? Yes Go to step 3 . No Go to step 4 .
3. O2 SENSOR HEATER OPERATION Turn the ignition off. NOTE: Wait a minimum of 10 minutes to allow the O2 Sensor to cool down before continuing the test. Allow the O2 Sensor voltage to stabilize at 5.0 volts. Turn the ignition on. With a scan tool, actuate the O2 Sensor heater. With the scan tool, monitor O2 Sensor voltage for at least 2 minutes. Does the voltage stay above 4.5 volts? Yes Go to step 4 . No Test complete.
4. O2 SENSOR Turn the ignition off. NOTE: Check for contaminants that may cause improper O2 Sensor operation, such as contaminated fuel, unapproved silicone, or evidence of oil or coolant. Disconnect the O2 Sensor harness connector. Turn the ignition on. With a scan tool, monitor the O2 Sensor voltage. NOTE: The voltage should be approximately 5.0 volts with the connector disconnected. Connect a jumper wire between the signal circuit and the return circuit in the O2 Sensor harness connector. NOTE: The voltage should drop from 5.0 volts to 2.5 volts with the jumper wire in place. Is the O2 Sensor voltage displayed on the scan tool as described? Yes Replace the O2 Sensor. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 5 .
5. O2 SENSOR SIGNAL CIRCUIT Using the wiring diagram/schematic as a guide, inspect the O2 Sensor Signal circuit and connectors between the O2 sensor and the PCM. Check the O2 Sensor signal circuit for a short to ground, open circuit, short to voltage, or high resistance. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 6 .
6. O2 SENSOR RETURN CIRCUIT Using the wiring diagram/schematic as a guide, inspect the O2 Sensor Return circuit and connectors between the O2 sensor and the PCM. Check the O2 Sensor return circuit for a short to ground, open circuit, short to voltage or high resistance. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 7 .
7. POWERTRAIN CONTROL MODULE (PCM) Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the O2 sensor and the PCM. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Monitor the scan tool data relative to the components tested in this procedure and wiggle test the wiring and connectors. Look for the data to change or for a DTC to set during the wiggle test. Refer to any Technical Service Bulletins that may apply. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

1. COMPARE TEMPERATURE SENSOR VALUES Turn the ignition off. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above - 7° C (19.4° F) until the engine coolant temperature is equal to ambient temperature. Turn the ignition on. Using a thermometer, measure and record the underhood and ambient temperatures. With a scan tool, read the ambient air temperature (AAT), engine coolant temperature (ECT), engine oil temperature (EOT) and intake air temperature (IAT) sensor values, as applicable. Are all temperature sensor values within 10° C (18° F) of the thermometer and the other sensor values? Yes Test complete. No Go to step 2 .
2. TEMPERATURE SENSOR WIRING OR CONNECTORS NOTE: Perform the following procedures for each sensor that was not within the specified range as described in the previous step. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the temperature sensor(s) and the applicable control module. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Turn the ignition on. Monitor the scan tool data relative to the sensor(s) and wiggle test the wiring and connectors. Look for the data to change or for a DTC to set during the wiggle test. Were any problems found? Yes Repair as necessary in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 3 .
3. SENSOR VOLTAGE Turn the ignition off. Disconnect the temperature sensor harness connector. Connect a jumper wire between the signal circuit and the sensor ground circuit in the sensor harness connector. Turn the ignition on. With a scan tool, read the sensor voltage. NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus.1 volt) with the jumper wire in place. Does the scan tool display the voltage as described above? Yes Go to step 4 . No Go to step 5 .
4. TEMPERATURE SENSOR Turn the ignition off. Remove the jumper wire from between the signal circuit and the sensor ground circuit in the sensor harness connector. Turn the ignition on. With a scan tool, read the sensor voltage. NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected. Does the scan tool display the voltage as described above? Yes Replace the sensor. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 5 .
5. SIGNAL CIRCUIT SHORTED TO GROUND Turn the ignition off. Measure the resistance between ground and the signal circuit in the sensor harness connector. Is the resistance above 100 ohms? Yes Go to step 6 . No Repair the signal circuit for a short to ground. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
6. SIGNAL CIRCUIT SHORTED TO SENSOR GROUND CIRCUIT Measure the resistance between the signal circuit and the sensor ground circuit in the sensor harness connector. Is the resistance above 100 ohms? Yes Go to step 7 . No Repair the signal circuit for a short to the sensor ground circuit. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
7. SIGNAL CIRCUIT HIGH RESISTANCE Turn the ignition off. Connect the temperature sensor harness connector. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the signal circuit at the sensor harness connector and at the applicable module connector (or by probing the appropriate terminal of the special tool #8815). Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 8 . No Repair the signal circuit for high resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
8. SENSOR GROUND CIRCUIT HIGH RESISTANCE Turn the ignition off. CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis. Using a voltmeter, perform a voltage drop test by backprobing the sensor ground circuit at the sensor harness connector and at the applicable module connector (or by probing the appropriate terminal of the special tool #8815). Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter. 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 can result in personal injury or death. Start the engine. Is the voltage below 0.5 volts? Yes Go to step 9 . No Repair the sensor ground circuit for high resistance. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
9. MODULE Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the sensor and the applicable control module. Look for any chafed, pierced, pinched, or partially broken wires. Look for broken, bent, pushed out or corroded terminals. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors. Look for the data to change or for the DTC to reset during the wiggle test. Refer to any Technical Service Bulletins that may apply. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace the applicable control module in accordance with the Service Information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

1. NO START PRE-TEST NOTE: The following list of items must be checked before continuing with any no start tests. The battery must be fully charged and in good condition. A low charged battery may produce invalid test results. If the battery is low, charge the battery and then attempt to start the vehicle by cranking the engine for 15 seconds, 3 consecutive times. This will allow any DTCs to set that may have been erased due to a dead battery. Attempt to communicate with the PCM using the scan tool. If the PCM is experiencing a no response condition, refer to «ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS»(ref-304334-S35563214642008110700000) for the proper tests. Read the PCM DTCs with the scan tool. If any DTCs are present, they must be repaired before continuing with any other No Start diagnostic tests. Refer to appropriate Engine ELECTRICAL DIAGNOSTICS article for the related P-code that is reported by the PCM. Inspect all fuses in the TIPM and the Junction Box. If an open fuse(s) is found, check the related circuit(s) for a short to ground or high resistance. Using a test light, check the Powers and Ground to the PCM. The test light must illuminate brightly as if jumpered across a battery. Attempt to communicate with the Instrument Cluster and VTSS. If you are unable to establish communications refer to «ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS»(ref-304334-S35563214642008110700000) for the proper Diagnostic procedures. The Sentry Key Immobilizer System must be operating properly. Check for proper communication with the scan tool and check for DTCs that may be stored in the Sentry Key Immobilizer Module (SKREEM). Repair the DTC(s) before continuing. If no DTCs are found, using the scan tool, select Clear PCM (BATT Disconnect). Crank the engine several times. Using the scan tool, read DTCs. If a DTC is present perform the appropriate DTC diagnostics before continuing. Were any problems found? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. OPEN FUSE Check for any open fuses in both TIPM or Junction Block that may be related to the no start condition. NOTE: If an open fuse is found, inspect the related circuit(s) for a short to ground or high resistance. Are any of the fuses open? Yes Replace the open fuse and check the related circuit(s) for a short to ground. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 3 .
3. SECONDARY INDICATORS PRESENT NOTE: Diagnose only the Secondary Indicators that would cause a no start. Ignition on, engine not running. With the scan tool, check the Secondary Indicators while cranking the engine that would cause a no start condition. Are there any Secondary Indicators present while cranking the engine? Yes Refer to appropriate Engine ELECTRICAL DIAGNOSTICS article and perform the tests related to the no start secondary indicator that is reported by the scan tool. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 4 .
4. POSSIBLE MECHANICAL PROBLEMS Check for any of the following conditions/mechanical problems. ENGINE VALVE TIMING - must be within specifications, check for broken timing components ENGINE COMPRESSION - must be within specifications ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks. Are there any engine mechanical problems? Yes Repair as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 5 .
5. FUEL PUMP DELIVERY Verify that the Fuel tank is not empty before continuing. Follow the diagnostics for «*CHECKING THE FUEL DELIVERY SYSTEM»(ref-304395-S35466817302008110700000) . Was the No Start condition solved after following the above diagnostic test? Yes Test Complete. No Check for contamination/water in the fuel. Make sure the fuel being used in this vehicle meets manufactures Fuel Requirement, refer to the service information. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .

1. FUEL PUMP MODULE NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair / replace as necessary. Turn the ignition off. 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 personal injury or death. Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter. Install the fuel pressure gauge. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off. NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). If the fuel pressure is not within specification refer to «*CHECKING THE FUEL DELIVERY SYSTEM»(ref-304395-S35466817302008110700000) . Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the engine. Monitor the fuel pressure gauge for a minimum of 5 minutes. NOTE: The pressure should not fall below 241 KPa (35 psi) Does the fuel pressure drop? Yes Replace Fuel Pump Module. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 2 .
2. FUEL INJECTOR(S) 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 personal injury or death. Remove special tool #C4390. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off. NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and fuel pump module. Monitor the fuel pressure gauge for a minimum of 5 minutes. NOTE: The pressure should not fall below 241 KPa (35 psi) Does the fuel pressure drop? Yes Replace the leaking fuel injectors. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Test Complete.

1. CHECKING FUEL PRESSURE Turn the ignition off. 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 personal injury or death. Install a fuel pressure gauge at the engine. Ignition on, engine not running. With a scan tool, actuate the Fuel Pump and observe the fuel pressure gauge. NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). Choose a conclusion that best matches your fuel pressure reading. Below Specification Go to step 2 . Within Specification Go to step 4 .
2. RESTRICTED FUEL SUPPLY LINE Turn the ignition off. 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 personal injury or death. Raise vehicle on hoist, and disconnect the fuel supply line at the fuel pump module. Install special tool #6539 (5/16") #6631(3/8") fuel line adapter and the fuel pressure gauge between the fuel supply line and the fuel pump module. Ignition on, engine not running. With the scan tool, actuate the Fuel Pump and observe the fuel pressure gauge. NOTE: Fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). Is the fuel pressure within specification? Yes Visually and physically inspect the fuel supply lines between the fuel tank and the fuel rail. Repair/replace as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 3 .
3. CHECKING THE FUEL PUMP INLET Turn the ignition off. 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 personal injury or death. Remove the Fuel Pump Module and Fuel Tank Module (if equipped), inspect the Fuel Pump Inlet and the bottom of the fuel tank for debris that could cause the fuel pump inlet to be plugged. Is the Fuel Inlet Strainer plugged? Yes Repair/Replace as necessary. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Replace the Fuel Pump Module. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .
4. FUEL PUMP MODULE NOTE: Before continuing visually and physically inspect the fuel delivery system for external leaks or damage. Repair / replace as necessary. Turn the ignition off. 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 personal injury or death. Install special tool #6539 (5/16") or #6631 (3/8") fuel line adapter. Install the fuel pressure gauge. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off. NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the engine. Monitor the fuel pressure gauge for a minimum of 5 minutes. NOTE: The pressure should not fall below 241 KPa (35 psi). Does the fuel pressure drop below 241 KPa (35 psi)? Yes Replace Fuel Pump Module. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Go to step 5 .
5. FUEL INJECTOR(S) 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 personal injury or death. Remove special tool #C4390. Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off. NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi). Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and fuel pump module. Monitor the fuel pressure gauge for a minimum of 5 minutes. NOTE: The pressure should not fall below 241 KPa (35 psi) Does the fuel pressure drop below 241 KPa (35 psi)? Yes Replace the leaking fuel injectors. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) . No Check the fuel for contaminants. Perform «PCM VERIFICATION TEST»(ref-304396-S07357759032008110700000) .