2.0L Engine - Service Information: Overview Jeep Compass I рестайлинг 2

DESCRIPTION

The 2.0 Liter (122 cu. in.) in-line four cylinder engine is a double over head camshaft with mechanical lash buckets and four valves per cylinder design. This engine is NOT free-wheeling; meaning that the pistons will contact the valves in the event of a timing chain failure.

The cylinders are numbered from front of the engine to the rear. The firing order is 1-3-4-2.

The engine serial number is located on the rear of the cylinder block. The serial number contains engine build date information.

The cross flow designed, aluminum cylinder head contains dual over-head camshafts with four valves per cylinder. The valves are arranged in two in-line banks. The intake valves face toward the front of the vehicle. The exhaust valves face the dash panel. The cylinder head incorporates powdered metal valve guides and seats. The cylinder head is sealed to the block using a multi-layer steel head gasket and retaining bolts.

Integral oil galleries provide lubrication passages to the variable camshaft timing phasers, camshafts, and valve mechanisms.

Note. Replacement cylinder heads will come complete with valves, seals, springs, retainers, keepers, lash buckets, and camshafts.

The world engine is equipped with Variable Valve Timing (VVT). This system advances and/or retards intake and/or exhaust camshaft timing to improve engine performance, mid-range torque, idle quality, fuel economy, and reduce emissions. The camshaft sprockets are integrated with the VVT assemblies and are serviced as an assembly. VVT assemblies are sometimes referred to as camshaft phasers.

OPERATION

The Variable Valve Timing (VVT) assemblies are actuated with engine oil pressure. The oil flow to the VVT assemblies are controlled by two Oil Control Valves (OCV). There is an OCV and Camshaft Position Sensor (CMP) for each camshaft. The OCV's consist of a Pulse Width Modulated (PWM) solenoid and a spool valve. The PCM actuates the OCV to control oil flow through the spool valve into the VVT assemblies. The VVT assembly consists of a rotor, stator, and sprocket. The stator is connected to the timing chain through the sprocket. The rotor is connected to the camshaft. Oil flow in to the VVT assembly rotates the rotor with respect to the stator, thus rotating the camshaft with respect to the timing chain. Thus, the VVT assemblies change valve timing by changing the relationship between the camshaft and the timing chain. An integral oil pressure activated pin is used to lock base camshaft timing for engine start up. Oil pressure releases the pin and allows the PCM to control cam timing once the engine is running. An infinitely variable valve timing position can be achieved within the limits of the hardware. The CMP monitors the position of the camshaft with respect to the crankshaft and provides feedback to the PCM.

Both camshafts have five bearing journal surfaces and two cam lobes per cylinder. The two front journals are larger to allow for feeding oil to the variable valve timing (VVT) camshaft phasers. Flanges on the third smaller journal control camshaft end play. At the rear of each camshaft is an integral cam sensor target.

Scheme 2

The front cam bearing cap spans both camshafts, and includes dowels for precise alignment. The front exhaust camshaft journal has a select fit bearing insert. This bearing is required to seal the oil passage to the camshaft phaser, because a portion of the lower bearing saddle is machined away for head bolt access. The select fit is required to minimize bearing clearance and oil leakage. An exhaust bearing grade (1, 2, or 3) is stamped into the front bearing cap adjacent to the exhaust cam journal. The bearings are also marked with the corresponding grade markings. If the bearing is replaced, the same grade must be used. Due to the unique purpose of this bearing, it may appear to have uneven wear patterns (1). Maximum wear of 0.05 mm (.002 in.) is acceptable. Unless the wear is excessive it is no cause for concern and the bearing should not be replaced. Cam bearing inspection should not be the sole reason for removal of the exhaust camshaft. The upper cam bearing may be replaced if the front bearing cap is removed. The lower cam bearing should be replaced if the camshaft is removed due to a failure of a component within the cylinder head.

The front intake cam journal has a full lower bearing saddle, and therefore, no bearing insert is required.

All small bearing caps have a formed-in arrow to assist in assembly. All small bearing cap arrows must point towards the center of the cylinder head. The small bearing caps are marked for position during the manufacturing process, and must be reinstalled in their original position.

The #1 small cap includes a passage to direct oil from the cylinder head oil gallery to the #1 small bearing journal, and into the camshaft as well. The hollow camshaft then distributes oil to the remainder of the small journals. Oil flowing out of each cam journal lubricates the valve tappets.

The #3 small cap is machined at the front and rear face to control camshaft end-play. This cap has dowels for precise alignment.

The camshaft is driven by the crankshaft via drive sprockets and a chain. The camshaft has precisely machined lobes to provide accurate valve timing and duration.

Scheme 3

1. Using a suitable tool, move camshaft as far rearward as it will go.
2. Zero dial indicator.
3. Move camshaft as far forward as it will go.
4. Record reading on dial indicator. For end play specification, refer to «SPECIFICATIONS»(ref-612695-S27170069432014043000000) .
5. If end play is excessive, check cylinder head and camshaft for wear; replace as necessary.

Scheme 4

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Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. Remove engine cover (1) by pulling upward.
2. Disconnect and isolate the negative battery cable.
3. Remove cylinder head cover . Refer to «COVER(S), CYLINDER HEAD, REMOVAL»(ref-612695-S16927086212014043000000) .
4. Raise and support the vehicle. Refer to «HOISTING, STANDARD PROCEDURE»(ref-612692-S42044915732014043000000) .
5. Remove the frame cover portion of the right splash shield. Refer to «SHIELD, SPLASH, FRONT WHEELHOUSE, REMOVAL»(ref-612710-S08980961332014043000000) .
6. Rotate engine to TDC (1).
7. Make sure camshaft timing marks (3) are in line with the cylinder head cover sealing surface.
8. Mark the chain link corresponding to timing marks (1) with a paint marker.
9. Remove timing tensioner plug (1) from front cover.
10. Insert small Allen wrench through timing tensioner plug hole and lift ratchet (2) upward to release the tensioner and push Allen wrench inward. Leave the Allen wrench installed during the remainder of this procedure.
11. Insert Locking Wedge (special tool #9701, Wedge, Locking) (1) between camshaft phasers.
12. Lightly tap Locking Wedge (special tool #9701, Wedge, Locking) (2) into place until it will no longer sink down. NOTE: Camshaft bearing caps should have been marked during engine manufacturing. For example, number one exhaust camshaft bearing is marked "E1>". CAUTION: DO NOT use a number stamp or a punch to mark camshaft bearing caps. Damage to bearing caps could occur.
13. Using a permanent ink or paint marker, identify location and position on each camshaft bearing cap.
14. Remove the front camshaft bearing cap.
15. Slowly remove the remaining intake and exhaust camshaft bearing cap bolts one turn at a time.
16. Remove intake camshaft (1) by lifting the rear of the camshaft upward.
17. Rotate the camshaft while lifting out of the front bearing cradle.
18. Lift the timing chain (2) off the sprocket (1).
19. Remove exhaust camshaft.
20. Secure timing chain with wire so that it does fall into the timing chain cover.

The valves are made of heat resistant steel. They have nitrided stems to prevent scuffing. Viton rubber valve stem seals are integral with the spring seats. The valves have single bead lock keepers to retain the springs.

The four valves per cylinder (two intake and two exhaust) are opened by using direct acting tappets which are actuated by the camshaft.

The die cast aluminum cylinder block is a two-piece assembly, consisting of the cylinder block and ladder frame. The block is an open deck design with cast in place cast iron cylinder liners. The cast iron cylinder liners are recessed below the aluminum deck surface. The ladder frame bolts to the cylinder block and does not incorporate the main bearing caps. This design offers a much stronger lower end and increased cylinder block and transaxle rigidity. The rear oil seal retainer is integral with the block and ladder frame. The ladder frame and block are serviced as an assembly.

Scheme 14

The engine serial number is located on the bottom of the ladder frame just behind the oil pan. The date can be seen with the oil pan in place.

Scheme 15

1. Deglazing of the cylinder walls may be done using a quality commercially available flex hone, if the cylinder bore is straight and round. 20-60 strokes depending on the bore condition, will be sufficient to provide a satisfactory surface. Use a light honing oil. Do not use engine or transmission oil, mineral spirits or kerosene. Inspect cylinder walls after each 20 strokes.
2. Honing should be done by moving the hone up and down fast enough to get a cross-hatch pattern. When hone marks intersect at 30-50 degrees, the cross hatch angle is most satisfactory for proper seating of rings.
3. A controlled hone motor speed between 200-300 RPM is necessary to obtain the proper cross-hatch angle. The number of up and down strokes per minute can be regulated to get the desired 30-50 degree angle. Faster up and down strokes increase the cross-hatch angle.
4. After honing, it is necessary that the block be cleaned again to remove all traces of abrasive.

The pistons are made of a cast aluminum alloy. The pistons have pressed-in pins attached to forged connecting rods. The piston pin is offset 0.8 mm (0.0314 in.) towards the thrust side of the piston. The connecting rods are a cracked cap design and are not repairable. The piston with rings, connecting rod and piston pin are serviced as an assembly.

Scheme 16

Note. Pistons and cylinder bores should be measured at normal room temperature, 21°C (70°F).

Piston and cylinder wall must be clean and dry. Piston diameter should be measured 90 degrees to piston pin (1).

Scheme 17

1. Measurement should be taken approximately 16 mm (0.629 in.) from the bottom of the skirt (2) as shown in illustration. NOTE: Correct piston to bore clearance must be established in order to assure quiet and economical operation.
2. Cylinder bores should be measured halfway down the cylinder bore and transverse (measurement location B) to the engine crankshaft center line shown in illustration. Refer to «SPECIFICATIONS»(ref-612695-S27170069432014043000000) .

Scheme 18

1. Remove the engine. Refer to «REMOVAL»(ref-612695-S29850061772014043000000) .
2. Remove the cylinder head. Refer to «CYLINDER HEAD, REMOVAL»(ref-612695-S25739607612014043000000) .
3. Remove the balance shaft module. Refer to «PUMP, ENGINE OIL»(ref-612695-S16148365782014043000000) .
4. Remove bolts (1) and the connecting rod bearing caps.
5. Carefully push the piston through the bore and use care not to damage the oil cooling jet or allow the end of connecting rod to hit the cylinder wall.

Scheme 19

1. Install bearing halves onto the connecting rod and lubricate bearing with clean engine oil.
2. Using a commercially available ring compressor, install the pistons into the cylinder bore. Use care and don't allow the connecting rod to hit the cylinder wall or damage the piston oil cooler jet.
3. Install new rod bearings and check bearing clearance.
4. Install the connecting rod bearing caps.
5. For new connecting rods, tighten bolts to: 5 N.m (44 in. lbs.). 25 N.m (18 ft. lbs.). plus an additional 180°.
6. For used connecting rods, tighten bolts to: 5 N.m (44 in. lbs.). 25 N.m (18 ft. lbs.). plus an additional 90°.
7. If required, install bearing halves (1 and 2) into bearing caps and lubricate bearing with clean engine oil.
8. Install the balance shaft module and check bearing clearance. Refer to «PUMP, ENGINE OIL»(ref-612695-S16148365782014043000000) .
9. Install the cylinder head. Refer to «CYLINDER HEAD, INSTALLATION»(ref-612695-S36887171582014043000000) .
10. Install the engine. Refer to «INSTALLATION»(ref-612695-S18608328862014043000000) .

Scheme 20

Scheme 21

1. Remove accessory drive belt.
2. Install Damper Holder (special tool #9707, Holder, Vibration Damper) (1) and remove damper retaining bolt.
3. Pull damper off crankshaft.
4. Remove front crankshaft oil seal (1) by prying out with a screw driver (2). Be careful not to damage the cover seal surface.

Scheme 22

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Scheme 25

1. Place seal (1) onto Front Crankshaft Seal Installer (special tool #9506, Installer, Oil Seal) (2) with seal spring towards the inside of engine.
2. Install new seal (1) by using Front Crankshaft Seal Installer (special tool #9506, Installer, Oil Seal) (2) and crankshaft damper bolt (3).
3. Press seal into front cover until Front Crankshaft Seal Installer (special tool #9506, Installer, Oil Seal) (1) seats against timing chain cover (3).
4. Remove Front Crankshaft Seal Installer (special tool #9506, Installer, Oil Seal) (1).
5. Install crankshaft vibration damper.
6. Oil the bolt threads and between the bolt head and washer.
7. Install damper retaining bolt and Damper Holder (special tool #9707, Holder, Vibration Damper) (1). Tighten bolt to 210 N.m (155 ft. lbs.).

Scheme 26

1. Remove transmission and flexplate (1). Refer to «FLEXPLATE, REMOVAL»(ref-612695-S06054680312014043000000) .
2. Insert a 3/16 flat bladed screwdriver (7) between the dust lip (8) and the metal case (4) of the crankshaft seal (1). Angle the screwdriver through the dust lip against metal case of the seal. Pry out seal. CAUTION: Do not permit the screwdriver blade to contact crankshaft seal surface. Contact of the screwdriver blade against crankshaft edge (chamfer) is permitted.
3. Check to make sure the seals garter spring is not on the crankshaft.

Scheme 27

Note. When installing seal, lubricate Seal Guide (special tool #9509, Installer, Oil Seal) with clean engine oil.

1. Place Seal Guide (special tool #9509, Installer, Oil Seal) (3) on crankshaft.
2. Position seal (2) over guide tool. Guide tool should remain on crankshaft during installation of seal. Ensure that the lip of the seal is facing towards the crankcase during installation.
3. Drive the seal into the block using Seal Driver (special tool #9706, Installer, Crankshaft Rear Oil Seal) (1) and Driver Handle (special tool #C-4171, Driver Handle, Universal) (4) until Seal Driver (special tool #9706, Installer, Crankshaft Rear Oil Seal) bottoms out against the block.
4. Install the flexplate (1) and transmission. Refer to «FLEXPLATE, INSTALLATION»(ref-612695-S37950307762014043000000) .

The engine mounting system consists of a four-point system utilizing two load-carrying mounts and two torque controlling mounts. The load-carrying mounts are located on each frame rail. The right and left mounts are hydro-elastic mounts. The two torque controlling mounts are attached to a fore/aft member and the front and rear of the engine.

The four-point engine mounting system minimizes the transmission of structure-borne engine noise to the passenger compartment. The load-carrying right and left mounts dampen and isolate vertical motion and vibration. The front and rear mount absorb torque reaction forces and torsional vibrations.

Scheme 28

1. Raise vehicle.
2. Remove fore aft member (3) to mount (4) bolts.
3. Remove mount through bolt (1).
4. Remove fore aft member (3) mounting bolts and remove.
5. Remove front mount (4).

Scheme 29

1. Position mount (4) and tighten bolts to 47 N.m (35 ft. lbs.).
2. Install fore aft member (3) and tighten bolts to 100 N.m (74 ft. lbs.).
3. Install mount through bolt (1) and tighten to 47 N.m (35 ft. lbs.).
4. Lower vehicle.

Scheme 30

1. Unlock the retainers (2) and remove the fresh air inlet duct (3) from air cleaner body (1).
2. Disconnect and isolate the negative battery cable.
3. Unlock and disconnect the electrical connectors (2) from the PCM (4).
4. Remove the mounting bolt (3) and ground wire (1).
5. Remove the air inlet tube (2) from the air cleaner body (1).
6. Disconnect the make-up air hose (3) from the air cleaner body.
7. Remove the support bracket bolt from the strut tower.
8. Pull upward to disengage the pins from the rubber grommets and remove the air cleaner body (1).
9. Support the transaxle with a suitable jack.
10. Remove the left mount through bolt (3).
11. Remove the left mount bracket to body frame rail fasteners (1).
12. Remove the mount (2).

Scheme 31

1. Position mount (2) in place.
2. Install left mount to frame rail bolts (1) and torque to 75 N.m (55 ft. lbs.).
3. Install mount through bolt (3) and torque to 100 N.m (74 ft.lbs.).
4. Remove jack.
5. Push down on the air cleaner body (1) to engage the pins into the grommets.
6. Install the support bracket bolt to the strut tower and tighten to 10 N.m (89 in. lbs.).
7. Install the air inlet tube (2) to the air cleaner body (1).
8. Connect the make-up air hose (3) to the air cleaner body.
9. Install the mounting bolt (3) with ground wire (1) and tighten to 12 N.m (106 in. lbs.).
10. Connect and lock the electrical connectors (2).
11. Connect the negative battery cable and tighten nut to 5 N.m (45 in. lbs.).
12. Install the fresh air inlet duct (3) on the air cleaner body (1) and lock the retainers (2).

Scheme 32

1. Remove rear mount retaining bolts (4).
2. Remove rear mount through bolt (1).
3. Remove oxygen sensor connector (2) from mount.
4. Remove rear mount (3).

Scheme 33

1. Position rear mount (3).
2. Install rear mount retaining bolts (4) and tighten to 50 N.m (37 ft. lbs.).
3. Install rear mount through bolt (1) and tighten to 47 N.m (35 ft. lbs.).
4. Install oxygen sensor connector (2) retainer to mount (3).

Scheme 34

Scheme 35

Scheme 36

1. Remove coolant reservoir (3) and set aside.
2. Remove power steering reservoir (2) and set aside.
3. Remove windshield washer bottle (1).
4. Remove power steering line support bracket (1) from engine mount.
5. Support transaxle with a block of wood and a suitable jack.
6. Remove engine mount through bolt (4).
7. Remove engine mount bracket bolts (3).
8. Remove engine mount retaining bolts.
9. Remove engine mount.

Scheme 37

Scheme 38

Scheme 39

1. Position right engine mount (1).
2. Install engine mount retaining bolts and tighten to 75 N.m (55 ft. lbs.).
3. Install engine mount adapter (2) and tighten bolts (3) to 68 N.m (50 ft. lbs.).
4. Install engine mount through bolt (4) and tighten to 88 N.m (65 ft. lbs.).
5. Remove jack.
6. Install power steering line support bracket (1) at engine mount.
7. Install windshield washer bottle (1).
8. Install power steering reservoir (2).
9. Install coolant reservoir (3).
10. Install engine cover.

Scheme 40

The lubrication system is a full-flow filtration, pressure feed type. The balance shaft module (BSM) is mounted below the ladder frame and chain driven by the crankshaft. The BSM consists of a non-serviceable pump, oil pressure relief valve, and a non-serviceable balance assembly.

Scheme 41

Note. Not all blocks have the bolt on timing chain oil squirter. Engine blocks either have a bolt-on oil squirter or a 1.0 mm hole (1) drilled into the oil gallery passage. Engine blocks with the 1.0 mm hole no longer use an oil squirter even though the threaded mounting hole may still be present.

Engine oil is drawn up through the pickup tube and is pressurized by the oil pump and routed through the full-flow filter to the main oil gallery running the length of the cylinder block. A diagonal hole in each bulkhead feeds oil to each main bearing. Drilled passages within the crankshaft route oil from main bearing journals to connecting rod journals. Balance shaft lubrication is provided through an internal oil passage at the #3 bearing location around the BSM mounting bolt. A vertical hole at the number one bulkhead routes pressurized oil through a filter screen and head gasket up to the cylinder head. The oil then divides into three passages; one to the intake cam phaser, one to the exhaust cam phaser and one to the camshafts. The passage to the camshafts divides to feed both of the hollow camshafts at the second cam journal. The rest of cam journals are feed oil through the hollow camshafts. The #1 cam journals are fed oil through the VVT oil passages. Oil passages to the phasers are directed through the OCV (oil control valves) to the #1 journals. The oil then flows through the camshafts then to the cam phasers. Oil returning to the pan from pressurized components supplies lubrication to the valve stems, cam lobes, and tappets. Cylinder bores and wrist pins are splash lubricated from directed slots on the connecting rod thrust collars.

There is both an Intake and an exhaust camshaft sensor on vehicles equipped with a World Engine. The variable valve timing system used on World Engines requires the exact position of both the intake and exhaust camshaft. The GPEC1 uses camshaft sensor data along with crankshaft data to determine the actual position of the camshafts. Intake and exhaust phaser oil control valves are required on World Engine vehicles using variable valve timing. The oil valves direct oil to the Intake and exhaust phasers. Oil pressure in the phasers moves the camshafts to an advanced or retarded position.

To resolve this inherent conflict between optimum high and low speed valve timing, the GPEC1 controlled engine uses a variable valve timing system. The variable valve timing system advances and retards valve timing by rotating the position of both the intake and exhaust camshafts. With this system, the intake valve opening can range from 80 to 120 crankshaft degrees after Top Dead Center. Likewise, the exhaust valve opening can range from 85 to 120 crankshaft degrees before Top Dead Center. This degree of flexibility provides many benefits, including: Improved Engine Performance, Increased Fuel Economy, Improved Idle Stability and Decreased Engine Emissions. In non operating condition, the camshaft stays in lockpin position of cam phases. This is 120 degrees ATDC for intake camshaft and 120 degrees BTDC for exhaust camshaft.

The variable valve timing system is electronically controlled and hydraulically operated. The GPEC1 receives information from many sensors to determine the optimum valve timing. It then pulse-width modulates oil control valves which direct oil to the cam phasers. The cam phasers use oil pressure to rotate the intake and exhaust camshafts. The rotation of the camshafts is referred to as cam phasing. Before the GPEC1 can begin commanding the camshaft phasing, several enabling conditions must be met

1. The engine oil temperature must be at least -6.6°C (20°F)
2. The oil control valve coil temperature must be less than 140°C (284°F)
3. Engine speed must be at least 600 to 1000 RPM to achieve minimum oil pressure.
4. Battery voltage must be at least 10 volts
5. And there must be no camshaft or crankshaft sensor faults, engine timing faults, or oil control valve faults

First we will examine variable valve timing enabling conditions, and then we will take a closer look at the inputs and outputs of the system

1. Accelerator pedal position sensor
2. Oil temperature sensor
3. Map sensor
4. Intake cam sensor
5. Exhaust cam sensor
6. Crankshaft sensor
7. GPEC1
8. Exhaust phaser oil control valve
9. Intake phaser oil control valve
10. Inputs
11. Engine control module
12. Outputs
13. Sensed battery voltage

A minimum oil temperature is required to enable variable valve timing operation. Oil temperature and viscosity also have an impact on the operation of variable valve timing after start-up. Oil is used to control the movement of the camshafts. An incorrect oil viscosity could adversely affect the operation of the system or even render the system inoperative. It may even set a fault code.

The accelerator pedal position sensor indicates how far the driver wants to open the throttle plate. The GPEC1 calculates an initial camshaft set point based on whether the accelerator pedal is at part throttle or wide open throttle.

The MAP sensor provides information regarding engine load.

Sensed battery voltage provides information regarding current system voltage. Sensed battery voltage must be at least 10 volts in order for the oil control valves to function properly.

This information allows the GPEC1 to adjust camshaft timing to achieve the best fuel economy, the best engine performance or a combination of both. The hall-effect crankshaft sensor provides RPM information and determines when the number one piston is approaching Top Dead Center. The sensor generates a signal as the tone wheel, attached to the crankshaft, rotates. The tone wheel has 60 teeth minus two. When the gap, created by the missing teeth passes by the sensor, a signal is produced that indicates the number one piston is at Top Dead Center. The GPEC1 uses crankshaft sensor data along with camshaft data to determine the actual position of the camshaft. There are two hall-effect camshaft sensors on engines equipped with variable valve timing. The GPEC1 uses camshaft sensor data along with crankshaft data to determine the actual position of the camshaft.

The GPEC1 individually controls each valve. It sends a pulse width modulated signal to move a spool within the outer casing of the valve. Depending upon spool movement, oil is directed through the passages to advance or retard cam timing. The oil control valve also has a special cleaning strategy at key-on. The cleaning strategy is known as "debris crush mode". At key-on the GPEC1 cycles the oil control valve on and off several (5) times to crush any debris in the oil control valve and prevent the spool valve from sticking. In non operating condition, the camshaft stays in lockpin position of cam phases. This is 120 degrees ATDC for intake camshaft and 120 degrees BTDC for exhaust camshaft.

There are two oil control valves. One valve directs oil to the intake cam phaser, the other valve directs oil to the exhaust cam phaser. The valves are designed and function in the same manner. The outer casing of each oil valve has five oil passages. A passage for pressurized supply oil. A passage to the advance chamber of the cam phaser. A passage to the retard chamber of the cam phaser. A passage for oil return from the advance chamber of the cam phaser. A passage for oil return from the retard chamber of the cam phaser. Oil flows through the passages and applies pressure to the cam phasers to change cam timing.

There are two cam phasers. One phaser controls the position of the intake camshaft. The other phaser controls the position of the exhaust camshaft. The phasers consist of a sprocket, a rotor vane, and a housing or stator. The exhaust cam phaser also consists of a front bushing and spring. We will discuss the purpose and function of the bushing and spring later. The housing is bolted and permanently fixed to the camshaft sprocket, while the rotor vane is bolted and permanently fixed to the camshaft. With this design, any movement of the rotor vane in relation to the housing will also move the camshaft. The phaser and sprocket are serviced as an assembly.

Camshaft and crankshaft sensors provide feedback to the GPEC1 regarding the actual position of the camshafts. The GPEC1 then compares the actual camshaft positioning with desired positioning. If the desired positioning is not achieved within a specified time, during the second key cycle a trouble code is set.

There are six new diagnostic trouble codes available to help you determine if the control circuit from the GPEC1 to the oil control valve is intact and operating properly. The codes identify whether the control circuit is open, shorted to ground, or shorted to power. Three trouble codes are related to intake camshaft positioning, the other three codes are specific to exhaust camshaft positioning.

The oil control valve contains both electrical and mechanical components. It is electrically controlled by the GPEC1. The electrical current that energizes the coil results in mechanical motion of the spool valve. It is possible to verify both the electrical and mechanical operation of the valve. The oil control valve consists of a coil that is energized to move a spool within an outer casing. The condition of the coil can be tested with a Digital Volt Ohmmeter or DVOM. With the DVOM set to measure resistance, check the coil for an open, a short to ground, or excessive resistance. The correct resistance value of the coil is between 6 and 8 ohms. The mechanical operation of the oil control valve can be tested using actuator commands on the scan tool. Remove the oil control valve, then navigate to the actuator menu and select the oil control valve. Use commands to activate the valve and watch as the spool valve moves back and forth inside the casing.

Because the cam phasers are hydraulically operated by engine oil, the condition of the oil is very important. The oil must be of the correct viscosity, not obstructed by debris, to maintain correct pressure. Maintaining the correct oil viscosity is critical to the operation of the variable valve timing system. The wrong oil viscosity may cause the variable valve timing to malfunction and trouble codes to set. The correct oil viscosity for this system is 5W20. Oil must be clean, unobstructed and free to flow through the variable valve timing system. Oil could become obstructed in oil passages located in the cylinder head, cylinder block, or even in the oil screen. In the event oil flow is obstructed, further diagnosis or disassembly may be required to pin point the source of the obstruction. The variable valve timing system relies on oil pressure to advance or retard the position of the camshaft. Insufficient oil pressure will adversely affect the operation of variable valve timing. The minimum oil pressure for this system is 15 psi at normal operating temperature.

Though not directly used to change camshaft positioning, the oil screen is an important component of the variable valve timing system. It helps to remove debris going to the variable valve timing components. The oil screen is located in the cylinder block, immediately below the cylinder head. Oil must pass through the oil screen before entering the oil control valve. The cylinder head must be removed to service the oil screen. The intention is not to service the oil screen during vehicle life.

How the cam phaser works. The cam phaser assembly has eight separate chambers; four advance chambers and four retard chambers. When camshaft advance is requested, oil enters all four advance chambers and exerts force on the rotor vane. Because the rotor vane is bolted to the camshaft, the entire camshaft profile moves along with the rotor vane. At the same time, oil is forced out of the retard chambers. When camshaft retard is requested oil enters the retard chambers to move the camshaft in the opposite direction. There is a lock pin on one side of the rotor vane that fits inside a recessed area in the housing. The lock pin ensures that the default position of the intake cam phaser is 120 crankshaft degrees full retard and the default position of the exhaust cam phaser is 120 crankshaft degrees full advance. When the engine is turned off, rotational force and inertia move the intake camshaft and rotor vane toward the retard position. The exhaust cam phaser includes a spring and bushing to work against the rotational force of the engine, allowing the exhaust cam phaser to lock in the fully advanced position. Under most conditions the cam phasers are returned to lock pin position when the engine is turned off. In the unique condition of an engine stall, which abruptly shuts off the engine, the cam phasers may not return to the lock pin position. In this case, the phasers will return to the lock pin position at the next start-up. Lock pin position is the most ideal cam timing for idle stability. When engine RPM exceeds approximately 600 to 1000 RPM, oil pressure unlocks the pins and variable valve timing resumes. Once enabling conditions are met, the GPEC1 uses input from sensors to calculate optimum valve timing.

There are four preprogrammed modes from which the GPEC1 bases initial valve timing.

1. Starting
2. Idle or Part throttle
3. Wide open throttle
4. Limp-in or Default

From each preprogrammed mode, the GPEC1 adjusts valve timing based on operating conditions.

GPEC1 has calculated optimum intake valve timing of 112 degrees after Top Dead Center and optimum exhaust valve timing of 97 degrees before Top Dead Center. The GPEC1 pulse width modulates the oil control valves to advance or retard the camshaft to their desired location. The spool valve inside the intake oil control valve is energized and moves to allow pressurized oil into the advance chambers of the intake cam phaser. At the same time, the spool valve inside the exhaust oil control valve is energized and moves to allow pressurized oil into the retard chambers of the exhaust cam phaser. Oil enters the advance chambers of the intake phaser and the retard chambers of the exhaust phaser. Oil pressure releases the lock pin from its locked position and pushes against the rotor vane. Both the rotor vanes are moved, advancing the intake camshaft and retarding the exhaust camshaft.

Scheme 42

Scheme 43

Scheme 44

1. Disconnect negative battery cable.
2. Remove engine cover.
3. Rotate hose clamp out of way.
4. Disconnect oil pressure sensor electrical connector.
5. Remove oil pressure sensor.
6. Disconnect variable valve timing solenoid electrical connector.
7. Remove variable valve timing solenoid mounting bolt.
8. Pull solenoid straight out of cylinder head.

Scheme 45

Scheme 46

1. Disconnect negative battery cable.
2. Remove engine cover.
3. Disconnect variable valve timing solenoid electrical connector.
4. Remove variable valve timing solenoid mounting bolt.
5. Pull solenoid straight out of cylinder head.

Scheme 47

Scheme 48

Scheme 49

1. Solenoid for front location 1/1. Note mounting tab location is different between front and rear solenoids.
2. Install solenoid into cylinder head.
3. Install mounting bolt and tighten to 12 N.m (9 ft. lbs.).
4. Install oil pressure sensor.
5. Connect electrical connector to oil pressure sensor.
6. Connect electrical connector to Variable valve timing solenoid.
7. Connect negative battery cable.
8. Install engine cover.

Scheme 50

Scheme 51

1. Rear variable valve timing solenoid. Note mounting tab location is different between front and rear solenoids.
2. Install solenoid into cylinder head.
3. Install mounting bolt and tighten to 12 N.m (9 ft. lbs.).
4. Connect electrical connector to Variable valve timing solenoid.
5. Connect negative battery cable.
6. Install engine cover.

An engine oil cooler is used on some engine packages. The cooler is a coolant-to-oil type and mounted between the oil filter and oil filter adapter.

The oil pressure switch is located on the left front side of the engine block. The oil pressure switch is a pressure sensitive switch that is activated by the engine's oil pressure (in the main oil gallery). The switch is a two terminal device (one terminal is provided to the wiring harness and the other terminal is the switch's metal housing that screws into the engine block).

The oil pressure switch is normally "Closed." The switch changes from a "Closed" circuit to an "Open" circuit, on increasing pressure of 7 psig. The oil pressure switch changes from an "Open" circuit to a "Closed" circuit, on decreasing pressure, between 2 psig and 4 psig.