
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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TEST ACTION APPLICABILITY
5 Turn ignition on, engine not running.
Erase trouble codes.All
Refer to symptom * CHARGING SYSTEM NO CODE TEST in the
CHARGING category.
6 Ignition Off
Disconnect the Field Harness Connector at back of Generator.
Note: Check connectors - Clean/repair as necessary.
Using an ohmmeter, measure resistance of one of the Generator Field Terminals at
the Generator to Ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair or replace the shorted Generator as necessary.
Perform Powertrain Verification Test VER-3A.
No®Go To 7
7 Ignition Off
Disconnect the PCM Connector.
Disconnect the Field Harness Connector at back of Generator.
Note: Check connectors - Clean/repair as necessary.
Using an ohmmeter, measure the Generator Field Driver Circuit from PCM Connec-
tor to ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Generator Field Driver Circuit short to ground.
Perform Powertrain Verification Test VER-3A.
No®Go To 8
8 Ignition off.
If there are no potential causes remaining, the PCM is assumed to be defective.
View repair optionsAll
Repair
Replace the Powertrain Control Module.
Perform Powertrain Verification Test VER-3A.
20
CHARGING
P-1594 CHARGING SYSTEM VOLTAGE TOO HIGH ÐContinued
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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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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
4 Engine Running
With the DRB, read trouble 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 5
5 Ignition Off
Using a Voltmeter, measure the voltage between the Generator Case and Battery (-)
side.
Caution: Ensure all Wires are clear of the engine's moving parts.
Start the engine.
Is the voltage above 0.4 volt?All
Ye s®Repair Generator Ground high resistance Generator Case to
Battery (-) side.
Perform Powertrain Verification Test VER-3A.
No®Go To 6
6 Ignition Off
Connect Voltmeter between the Generator (12V) B+ Terminal and the Battery (+)
side.
Caution: Ensure all Wires are clear of the engine's moving parts.
Start the engine.
Is the voltage above 0.4 volt?All
Ye s®Repair the B(+) Circuit for high resistance between the Generator
and Battery.
Perform Powertrain Verification Test VER-3A.
No®Go To 7
7 Turn engine off, ignition key on.
With the DRB, read Battery voltage and record.
Using a Voltmeter, measure Battery voltage B(+) to B(-) Terminal.
Record second voltage reading.
Compare the two voltage readings.
Is the voltage difference less than one volt?All
Ye s®Test Complete.
Perform Powertrain Verification Test VER-3A.
No®Go To 8
8 Ignition Off
Disconnect the PCM Connector.
Note: Check connectors - Clean/repair as necessary.
Using a voltmeter, measure the fused B(+) at PCM.
Is the voltage within one volt of the DRB recorded reading?All
Ye s®Repair the B(+) Circuit for high resistance between the PCM and
the Battery.
Perform Powertrain Verification Test VER-3A.
No®Go To 9
25
CHARGING
* CHECKING CHARGING SYSTEM OPERATION WITH NO DTC'S Ð
Continued
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Symptom:
P-0106 BAROMETRIC PRESSURE OUT OF RANGE
When Monitored and Set Condition:
P-0106 BAROMETRIC PRESSURE OUT OF RANGE
When Monitored: With the ignition key on at less than 350 milliseconds and engine speed
at less than 255 RPM.
Set Condition: The PCM senses the voltage from the MAP sensor to be less than 2.196
volts but above 0.019 volt for 300 milliseconds
POSSIBLE CAUSES
MAP SENSOR 5V SUPPLY CIRCUIT OPEN
MAP SENSOR 5V SUPPLY CIRCUIT SHORT TO GROUND
MAP SENSOR SIGNAL CIRCUIT OPEN
MAP SENSOR SIGNAL CIRCUIT PARTIAL SHORT TO GROUND
MAP SENSOR WIRING HARNESS INTERMITTENT DEFECT
MAP SENSOR WIRING HARNESS OBSERVABLE DEFECT
MAP SENSOR DEFECTIVE
PCM DEFECTIVE (VOLTAGE HIGH)
PCM DEFECTIVE (VOLTAGE LOW)
TEST ACTION APPLICABILITY
1 Ignition On, Engine Not Running
With the DRB, read the MAP Sensor voltage.
Is the voltage below 2.2 volts?All
Ye s®Go To 2
No®Go To 11
2 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Turn the ignition on, engine not running.
Note: Check connectors - Clean/repair as necessary.
Using a Voltmeter, measure voltage of the 5-Volt Supply Circuit at the Map Sensor
Connector.
Is the voltage above 4.5 volts?All
Ye s®Go To 3
No®Go To 7
27
DRIVEABILITY
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TEST ACTION APPLICABILITY
3 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Ignition on, with engine not running.
With the DRB, read the MAP Sensor voltage.
Is the voltage above 4.9 volts?All
Ye s®Replace the MAP Sensor.
Perform Powertrain Verification Test VER-2A.
No®Go To 4
4 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure resistance of the MAP Sensor Signal Circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 5
No®Repair the open MAP Sensor Signal Circuit between MAP Sensor
and PCM.
Perform Powertrain Verification Test VER-2A.
5 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Ignition on, with engine not running.
With the DRB, read the MAP Sensor voltage.
Is the voltage above 2.2 volts?All
Ye s®Repair the MAP Sensor Signal Circuit for a partial short to
ground.
Perform Powertrain Verification Test VER-2A.
No®Go To 6
6 If there are no potential causes remaining, the PCM is assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-2A.
7 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
Using an Ohmmeter, measure the resistance of the 5-Volt Supply Circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 8
No®Repair the open 5-Volt Supply Circuit between MAP Sensor and
PCM Connectors.
Perform Powertrain Verification Test VER-2A.
28
DRIVEABILITY
P-0106 BAROMETRIC PRESSURE OUT OF RANGE ÐContinued
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TEST ACTION APPLICABILITY
8 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Disconnect the Powertrain Control Module Connector.
Note: Check connectors - Clean/repair as necessary.
With an Ohmmeter, measure the 5-Volt Supply Circuit to ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the 5-Volt Supply Circuit for a short to ground.
Perform Powertrain Verification Test VER-2A.
No®Go To 9
9 Ignition Off
Disconnect the MAP Sensor Electrical Connector.
Note: Check connectors - Clean/repair as necessary.
Ignition on, with engine not running.
With the DRB, read the MAP Sensor voltage.
Is the voltage above 2.2 volts?All
Ye s®Repair the MAP Sensor Signal Circuit for a partial short to
ground.
Perform Powertrain Verification Test VER-2A.
No®Go To 10
10 If there are no potential causes remaining, the PCM is assumed to be defective.
View repair options.All
Repair
Replace the PCM.
Perform Powertrain Verification Test VER-2A.
11 Ignition On, Engine Not Running
Wiggle the Wiring Harness from the MAP Sensor to the Powertrain Control Module.
Monitor the MAP Sensor voltage with the DRB, while wiggling the Wiring Harness.
Did the voltage go below 2.2 volts?All
Ye s®Repair Wiring as necessary where wiggling caused voltage drop.
Perform Powertrain Verification Test VER-2A.
No®Go To 12
12 Ignition Off
Using the schematic as a guide, inspect the Wiring and Connectors.
Were any problems found?All
Ye s®Repair as necessary.
Perform Powertrain Verification Test VER-2A.
No®Test Complete.
29
DRIVEABILITY
P-0106 BAROMETRIC PRESSURE OUT OF RANGE ÐContinued
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