DESCRIPTION
Note. All engines use a fixed ignition timing system. Basic ignition timing is not adjustable. All spark advance is determined by the Powertrain Control Module (PCM).
The ignition system used on these engines is referred to as coil on plug. The system's four main components are the coils, crankshaft position sensor, spark plugs, and camshaft position sensors. The coil on plug ignition system utilizes an ignition coil for every cylinder. The ignition coils are mounted directly over the each spark plug.
OPERATION
The crankshaft position sensor and camshaft position sensor are hall effect devices. The camshaft position sensor and crankshaft position sensor generate square wave pulses that are inputs to the Powertrain Control Module (PCM). The PCM determines engine position from these sensors. The PCM calculates injector sequence and ignition timing from crankshaft AND camshaft position.
When the knock sensor detects a knock in one of the cylinders on the corresponding bank, it sends an input signal to the Powertrain Control Module (PCM). In response, the PCM retards ignition timing for all cylinders by a scheduled amount.
Knock sensors contain a piezoelectric crystal which constantly vibrates and sends an input voltage (signal) to the PCM while the engine operates. As the intensity of the crystal's vibration increases, the knock sensor output voltage also increases.
The voltage signal produced by the knock sensor increases with the amplitude of vibration. The PCM receives the knock sensor voltage signal as an input. If the signal rises above a predetermined level, the PCM will store that value in memory and retard ignition timing to reduce engine knock. If the knock sensor voltage exceeds a preset value, the PCM retards ignition timing for all cylinders. It is not a selective cylinder retard.
The PCM ignores knock sensor input during engine idle conditions. Once the engine speed exceeds a specified value, knock retard is allowed.
Knock retard uses its own short term and long term memory program.
Long term memory stores previous detonation information in its battery-backed RAM. The maximum authority that long term memory has over timing retard can be calibrated.
Short term memory is allowed to retard timing up to a preset amount under all operating conditions (as long as RPM is above the minimum RPM) except at Wide Open Throttle (WOT). The PCM, using short term memory, can respond quickly to retard timing when engine knock is detected. Short term memory is lost any time the ignition key is turned off.
Note. Over or under tightening the sensor mounting bolts will affect knock sensor performance, possibly causing improper spark control. Always use the specified torque when installing the knock sensors.
| CAUTION | Cleaning platinum plugs may damage the platinum center electrode or the thin platinum pad. |
Scheme 3
| 1 - APPLY ANTI-SEIZE COMPOUND HERE ONLY |
|---|
| 2 - PLATINUM SPARK SURFACE |
The spark plugs are platinum resistor design. They have resistance values of 3, 500 to 20, 000 ohms when checked with at least a 1000 volt tester. For spark plug identification and specifications. Refer to SPECIFICATIONS .
Do not use an ohm meter to check the resistance of the spark plugs. This will give an inaccurate reading.
When the spark plugs use a single or double platinum tips, they have a recommended service life of 100, 000 miles for normal driving conditions per schedule A in this information. The spark plugs have a recommended service life of 75, 000 miles for severe driving conditions per schedule B in this information. A thin platinum pad (2) is welded to both or just the center electrode end(s). Extreme care must be used to prevent spark plug cross threading, incorrect gapping and ceramic insulator damage during plug removal and installation.
Mopar® Nickel-Graphite Anti-Seize compound is applied to the thread area (1) to prevent damage to the spark plug during removal and installation.
This vehicle is equipped with a Wireless Ignition Node (WIN). The WIN, along with the FOB with Integrated Key (FOBIK) are the primary components of the keyless ignition system. The only visible component of the WIN is the ignition switch located on the face of the instrument panel just to the inboard side of the steering column. The remainder of the WIN including its mounting provisions and electrical connections are concealed within the instrument panel.
In addition to replacing a conventional keyed ignition switch, the WIN is an integrated electronic receiver that serves as the base station in the vehicle. It communicates with other electronic modules in the vehicle over the Controller Area Network (CAN) data bus.
The WIN interfaces with the Remote Keyless Entry (RKE) FOBIK and the Tire Pressure Monitor (TPM) sensors (if equipped) using Radio Frequency (RF) communication, with the Sentry Key Immobilizer System (SKIS) transponder within the FOBIK using Low Frequency (LF) RF communication.
The WIN cannot be adjusted or repaired, but is flash update capable. If ineffective or damaged the entire WIN must be replaced. Refer to RECEIVER, WIRELESS IGNITION NODE, REMOVAL .