Symptom:
P-1594 CHARGING SYSTEM VOLTAGE TOO HIGH
POSSIBLE CAUSES
GENERATOR FIELD DRIVER CIRCUIT SHORT TO GROUND
GENERATOR SHORTED
PCM DEFECTIVE (CHARGING SYSTEM)
PCM BATT TEMP NOT W/I þ12 DEGREES C (10 DEGREES F) UNDER HOOD TEMP
PCM VOLT & TARGET CHARGING VOLT DIFFER BY > 1.0 V
TEST ACTION APPLICABILITY
1 Ignition on, engine not running.
Note: Battery must be fully charged.
Note: Generator Belt tension and condition must be checked before con-
tinuing.
With the DRB, actuate the Generator Field Driver.
Using a voltmeter, backprobe the Generator Field Driver Circuit voltage in back of
Generator.
Does the DRB show voltage shift low to high?All
Ye s®Go To 2
No®Go To 6
2 Ignition On, Engine Not Running
With the DRB, stop the Generator Field Driver actuation.
Read the target charging voltage.
Is the target charging voltage between 13.0 to 14.9 volts?All
Ye s®Test Complete.
No®Go To 3
3 Engine running.
Manually set the engine speed to 1600 RPM.
With the DRB, read both the voltage and the target charging voltage.
Compare the9target9to the9volt9reading.
Watch for up to 5 minutes, if necessary, for a 1.0 volt difference or more.
Was there more than a 1.0 volt difference?All
Ye s®Replace PCM.
Perform Powertrain Verification Test VER-3A.
No®Go To 4
4 Ignition On, Engine Not Running
Using the DRB Temperature Probe, measure the under hood temperature near PCM.
With the DRB, read the BTS temperature.
Is the Battery Temperature within þ12 degrees C (10 degrees F) of the under hood
temperature?All
Ye s®Go To 5
No®Replace PCM.
Perform Powertrain Verification Test VER-3A.
19
CHARGING
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Symptom:
P-1682 CHARGING SYSTEM VOLTAGE TOO LOW
When Monitored and Set Condition:
P-1682 CHARGING SYSTEM VOLTAGE TOO LOW
When Monitored: With no other charging system codes set. With the ignition on and the
engine running above 1500 RPM.
Set Condition: The battery sensed voltage is 1 volt below the charging system goal for 25
seconds. The PCM senses the battery voltage, turns off the field driver and senses the
battery voltage again. If the voltages are the same, the code is set.
POSSIBLE CAUSES
ASD RELAY OUTPUT CIRCUIT OPEN
GENERATOR FIELD DRIVER CIRCUIT OPEN
GENERATOR DEFECTIVE
GENERATOR DEFECTIVE (B)
PCM DEFECTIVE
TEST ACTION APPLICABILITY
1 Start engine, and allow it to idle.
Note: Battery must be fully charged.
Note: Generator Belt tension and condition must be checked before con-
tinuing.
With the DRB, read the Target Charging voltage.
Is the Target Charging voltage above 15.1 volts?All
Ye s®Go To 2
No®Go To 6
2 Ignition On, Engine Not Running
Using DRB Temperature Probe, measure the under hood temperature near PCM.
With the DRB, read the Ambient/BAT Temp.
Is the battery temperature within þ12 degrees C (10 degrees) of the under hood
temperature?All
Ye s®Go To 3
No®Replace the PCM.
Perform Powertrain Verification Test VER-3A.
21
CHARGING
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TEST ACTION APPLICABILITY
3 Ignition Off
Note: Battery must be fully charged.
Note: Generator Belt tension and condition must be checked before con-
tinuing.
Disconnect the Generator Field Connector.
Disconnect PCM connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the ASD Output Circuit from PCM
Connector to Field Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 4
No®Repair the ASD Relay Output Circuit, open circuit.
Perform Powertrain Verification Test VER-3A.
4 Ignition Off
Note: Battery must be fully charged.
Note: Generator belt tension and condition must be checked before continu-
ing.
Disconnect the Generator Field Connector.
Disconnect the PCM Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the Generator Field Driver Circuit
from PCM Connector to Generator Field Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the open Driver Circuit.
Perform Powertrain Verification Test VER-3A.
5 If there are no potential causes remaining, the Generator is assumed to be defective.
View repair options.All
Repair
Repair or replace the Generator as necessary.
Perform Powertrain Verification Test VER-3A.
6 Ignition Off
Note: Battery must be fully charged.
Note: Generator Belt tension and condition must be checked before con-
tinuing.
Disconnect the Generator Field Connector.
Disconnect the PCM Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the ASD Output Circuit from PCM
Connector to Field Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 7
No®Repair the ASD Relay Output Circuit, open circuit.
Perform Powertrain Verification Test VER-3A.
22
CHARGING
P-1682 CHARGING SYSTEM VOLTAGE TOO LOW ÐContinued
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TEST ACTION APPLICABILITY
7 Ignition Off
Note: Battery must be fully charged.
Note: Generator belt tension and condition must be checked before continu-
ing.
Disconnect the Generator Field Connector.
Disconnect the PCM Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the Generator Field Driver Circuit
from PCM Connector to Generator Field Connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 8
No®Repair the open Driver Circuit.
Perform Powertrain Verification Test VER-3A.
8 If there are no potential causes remaining, the Generator is assumed to be defective.
View repair options.All
Repair
Repair or replace the Generator as necessary.
Perform Powertrain Verification Test VER-3A.
23
CHARGING
P-1682 CHARGING SYSTEM VOLTAGE TOO LOW ÐContinued
ProCarManuals.com
Symptom:
* CHECKING CHARGING SYSTEM OPERATION WITH NO DTC'S
POSSIBLE CAUSES
TROUBLE CODES PRESENT
VOLTAGE DIFFERENCE >= 1 VOLT
GENERATOR FIELD TERMINAL INTERMITTENT DEFECTIVE
GENERATOR GROUND CIRCUIT HIGH RESISTANCE
B+ CIRCUIT HIGH RESISTANCE (0.4 VOLT)
B+ CIRCUIT HIGH RESISTANCE (1 VOLT)
PCM DEFECTIVE (CHARGING SYSTEM NO CODE)
GENERATOR BELT VISIBLY DEFECTIVE
TROUBLE CODES PRESENT 1600 RPM
TEST ACTION APPLICABILITY
1Note: Battery condition must be verified prior to this test.
Inspect the Generator Belt tension and condition.
Is the Generator Belt in good condition?All
Ye s®Go To 2
No®Repair as necessary.
Perform Powertrain Verification Test VER-3A.
2 Engine Running
With the DRB, set engine speed to 1600 RPM for 30 seconds.
With the DRB, return the engine to idle speed and read codes.
Are there any Charging System trouble codes?All
Ye s®Refer to Symptom List for problems related to Charging.
Perform Powertrain Verification Test VER-3A.
No®Go To 3
3 Turn ignition on. (Engine off)
With the DRB, actuate the Generator field.
Using a Voltmeter, backprobe Generator Field Driver Terminal at the back of
Generator.
Note: The voltage should cycle from 7.2 volts to Battery voltage every 1.4
seconds, at both Terminals.
While monitoring the Voltmeter, wiggle the field Terminals back to the PCM and ASD
Relay.
Was there any interruption in the normal cycle between 7.2 volts and Battery
voltage?All
Ye s®Repair the Wire where wiggling interrupted the voltage cycle.
Perform Powertrain Verification Test VER-3A.
No®Go To 4
24
CHARGING
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TEST ACTION APPLICABILITY
12 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Remove any spark plug wire.
Observe the Secondary KV Line.
Is the open secondary voltage at least 25 KV?All
Ye s®Go To 13
No®Replace the Ignition Coil.
Perform VERIFICATION TEST VER-5A2.
13 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Follow the equipment manufacturer's procedure for pattern analysis.
Is the secondary ignition pattern OK?All
Ye s®Go To 14
No®Repair the indicated component in the Secondary Ignition Sys-
tem.
Perform VERIFICATION TEST VER-5A2.
14 The following are possible causes for mis-fire:
Injector harness connectors, ignition coil circuit, spark plug, mechanical engine
problem, PCM power grounds, irregular cam and crank signal, injectors, restricted
exhaust, intake restriction, PCM, Evap System, EGR System, damaged trigger
wheel, and
accessory drive belts.
Do any of the above causes exist?All
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Go To 15
15The following additional items should be checked as possible mechanical
problems:
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions
ENGINE PCV SYSTEM - must flow freely
ENGINE DRIVE SPROCKETS - must be properly positioned
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; control wire not connected to
correct injector
Are there any engine mechanical problems?All
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Test Complete.
103
DRIVEABILITY
P-0300 MULTIPLE CYLINDER MIS-FIRE ÐContinued
ProCarManuals.com
TEST ACTION APPLICABILITY
12 Engine Off.
Connect a suitable engine analyzer to the engine.
Allow the Engine to idle.
NOTE: If the Engine will not idle, maintain a constant RPM above idle.
NOTE: Set the scope to read display or parade pattern.
Follow the equipment manufacturer's procedure for pattern analysis.
Is the secondary ignition pattern OK?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Go To 13
No®Repair the indicated component in the Secondary Ignition Sys-
tem.
Perform VERIFICATION TEST VER-5A2.
13 With the DRB, read the FREEZE FRAME DATA.
Use the freeze frame data and attempt to determine the cause of the misfire.
In the FREEZE FRAME, is the ENGINE RPM over 3000 and the operating temp
normal?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Lab scope cam and crank sensor, check valve timing, running
vacuum test.
Perform VERIFICATION TEST VER-5A2.
No®Go To 14
14The following additional items should be checked as possible mechanical
problems:
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions
ENGINE PCV SYSTEM - must flow freely
ENGINE DRIVE SPROCKETS - must be properly positioned
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; control wire not connected to
correct injector
Are there any engine mechanical problems?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Go To 15
15 The following are other possible causes for mis-fire:
Injector harness connectors, ignition coil circuit, spark plug, mechanical engine
problem, PCM power grounds, irregular cam and crank signal, injectors, restricted
exhaust, intake restriction, PCM, Evap System, EGR System, damaged trigger
wheel, and
accessory drive belts.
Do any of the above causes exist?ENGINE - 3.0L V6
and/or ENGINE -
3.3L V6 and/or EN-
GINE - 3.8L V6
and/or ENGINE -
3.3L V6 FFV
Ye s®Repair as necessary.
Perform VERIFICATION TEST VER-5A2.
No®Test Complete.
107
DRIVEABILITY
P-0305 CYLINDER #5 MIS-FIRE ÐContinued
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