Electrical and Ignition Control Parameters

NOTE: These parameters indicate the condition of the vehicle electrical system. They also include input signals from the ignition system and from the knock sensor to the logic module, as well as logic module output commands to control ignition timing.


ALTERNATOR LAMP
ALTERNATOR LAMP_ - XXX RANGE: ON - OFF

This parameter indicates the status of the signal to the charging system warning lamp.


BATTERY VOLTAGE
BATTERY VOLTS - XX.X RANGE: 0 to 15.7 volts

Chrysler charging systems are controlled by the logic module, and the voltage regulator is part of the engine control system. Therefore, the logic module receives a direct input signal that indicates the battery voltage at any time.

Although the measurement range is 0 to 15.7 volts, the reading should be close to normal charging system regulated voltage with the engine running. This is typically 13.0 to 15.0 volts at idle. Check the reading against actual voltage measured at the battery or alternator. Check vehicle specifications for exact values.


BATTERY TEMPERATURE
BATT TEMP(°F) - XXX RANGE: -40 to 389°

BATT TEMP(°C) - XXX RANGE: -40 to 199°

These analog parameters on 1991 and later vehicles indicate the approximate temperature of the battery. The logic module uses the battery temperature sensor signal to regulate the computer controlled charging system. A cold battery is charged at a higher rate than a warm battery.

You can change the measurement units on the scanner from degrees Fahrenheit (°F) to degrees Celsius (°C). The preset measurement is F.

Battery temperature in For C is not available on 1990 and earlier vehicles. Battery temperature sensor voltage, however, is available on all 1989 and later vehicles.


BATTERY TEMPERATURE VOLTAGE
BATT TEMP(V) - X.X RANGE: 0 to 5.1 volts

Battery temperature (BATT TEMP) voltage is a direct voltage reading from the battery temperature sensor. Sensor voltage and temperature are inversely related. Low temperature produces a high voltage signal; high temperature produces low voltage.

The battery temperature sensor is a variable resistor in parallel with a 5-volt reference signal to the logic module. On early systems, it is part of the power module. On SMEC and SBEC systems, it is part of the logic board.


DESIRED CHARGING VOLTAGE
DES CHARGE(V) - XX.X RANGE: 0 to 15.7 volts

This analog parameter on 1990 and later vehicles indicates the desired charging voltage that the logic module is trying to maintain. You can compare the DES CHARGE (V) desired voltage to the BATTERY VOLTS actual voltage to help troubleshoot electrical problems.


SPARK ADVANCE
SPARK ADV(°BTC) - XXX RANGE: -90 to +90°

SPARK ADV (°BTC) is an analog output parameter from the logic module that indicates the total spark advance or retard being commanded by the logic module, not including base timing.


TOTAL ADVANCE
TOTAL ADV(°BTC) - XXX RANGE: -90 to +90°

On some 1990 and later cars, TOTAL ADV (°BTC) is an analog output parameter from the logic module that indicates the total spark advance or retard being commanded by the logic module, including base timing.


TOTAL KNK RTD (°) - XX RANGE: 0 to 90°

KNK RTD CYL 1(°) - XX RANGE: 0 to 90°

KNK RTD CYL 2(°) - XX RANGE: 0 to 90°

KNK RTD CYL 3(°) - XX RANGE: 0 to 90°

KNK RTD CYL 4(°) - XX RANGE: 0 to 90°

Knock retard (°) indicates the amount of spark advance removed by the logic module when the detonation sensor senses knock. Timing is retarded from the optimum advance for existing speed and load Knock retard does not indicate that timing is retarded after top dead center. It indicates the amount of advance that has been taken away.

Typically, the logic module will retard timing from maximum advance in 5 degree increments until detonation stops or until 15 degrees have been removed from maximum advance. Advance is restored at approximately 2 degrees per second. Knock retard is cancelled below 1000 rpm.

On non-turbocharged engines, the scanner displays total knock retard for all cylinders as TOTAL KNK RTD (°). For turbocharged 4-cylinder engines, the scanner displays knock retard for individual cylinders.


KNOCK SENSOR VOLTAGE
KNOCK SENSOR(V) - X.X RANGE: 0 to 5.0 volts

KNOCK SENSOR(V) is the actual voltage signal sent to the logic module by the knock sensor. When the KNOCK SENSOR(V) reading is high, the knock retard parameters should indicate some amount of timing retard.


Z1 VOLTAGE
Z1 VOLTAGE - XXXXXX RANGE: ACTIVE - INACTIVE

On 1989 and later vehicles, voltage on circuit Z1 is active, or high, when the auto shutdown relay is energized.


B1 VOLTAGE
B1 VOLTAGE - XXXXXX RANGE: ACTIVE - INACTIVE

On 1989 and later vehicles, voltage on circuit B1 is active, or high, with the ignition switch in RUN. It is inactive, or low, with the ignition switch in START when the engine is cranking.


IGNITION CYCLES
IGN CYCLES - XX RANGE: 0 to 50

This parameter on some 1989 and later vehicles indicates the number of times the engine has been started since the last fault code was set or codes were cleared.


AUTOMATIC SHUTDOWN RELAY
AUTO SHUTDOWN - XXX RANGE: ON - OFF

On some 1989 and later vehicles, AUTO SHUTDOWN is a discrete parameter that indicates whether or not the logic module has ordered the auto shutdown relay to turn on. The auto shutdown relay provides power to the fuel pump, the ignition coil, and the fuel injectors. AUTO SHUTDOWN should read ON whenever the engine is running.


BALLAST BYPASS RELAY
BALLAST BYPASS - XXX RANGE: ON - OFF

This discrete parameter on some 1991 and later vehicles indicates the status of the ballast bypass relay for the ignition starting circuit. It should be ON during cranking and OFF for normal engine operation.


CRANKSHAFT AND CAMSHAFT POSITION SENSORS
CRANK SENSOR - XXX
RANGE: YES - NO
CAM SENSOR - XXX

These parameters let you look at the status of the crank and cam sensor signals used in direct ignition systems (DIS). The cam sensor signal is used for fuel injection timing and cylinder identification. The crank sensor signal is used to control fuel injection quantity and determine engine speed and spark advance. When starting or running the engine, these parameters must display YES. These parameters are useful when troubleshooting a no- start problem.



IGNITION CYCLES
IGN CYCLES 1 - XXX

IGN CYCLES 2 - XXX RANGE: 0 to 127

IGN CYCLES 3 - XXX

These parameters indicate the number of times the engine has been started since the last three faults were set or codes were cleared. IGN CYCLES 1 pertains to the most recent fault, IGN CYCLES 2 the second- most recent, and lGN CYCLES 3 the third-most recent.