DTC P0622
Diagnostic Instructions
DTC Descriptor
| DTC P0622: Generator F-Terminal Circuit
Malfunction |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
B+
|
P0622, P0625
|
P0622, P0625
|
-
|
-
|
Control
|
P0621, P2500
|
P0621, P2500
|
P0621, P2501
|
-
|
Signal
|
P0622, P0625
|
P0622, P0625
|
P0622, P0626
|
P0622
|
|
| |
Circuit/System Description
The engine control module (ECM) uses the generator field duty
cycle control circuit, or F-terminal circuit, to monitor the duty
cycle of the generator. The generator field duty cycle control
circuit connects to high side of the field windings in the
generator. A pulse width modulated (PWM) high side driver in the
voltage regulator turns the field windings ON and OFF. The ECM uses
the PWM control input to determine the generator load on the
engine. This allows the ECM to adjust the idle speed to compensate
for high electrical loads. The ECM monitors the status of the
generator field duty cycle control circuit. When the ignition is ON
and the engine is OFF, the ECM should detect a duty cycle near 0%.
When the engine is running, the duty cycle should be between
5-99%.
Conditions for Running the DTC
| • |
Ignition ON engine OFF, for
the Ignition ON test. |
| • |
Engine running, engine speed
less than 3 000 RPM for the RUN test. |
Conditions for Setting the DTC
| • |
Ignition ON engine OFF, the
ECM detects a PWM signal that is greater than 65% for 5 s.
|
| • |
Engine running, the ECM
detects a PWM signal that is less than 5% for 15 s. |
Action Taken When the DTC Sets
DTC P0622 is a C type DTC.
Conditions for Clearing the DTC
DTC P0622 is a C type DTC.
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Charging System Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Engine running, observe the scan tool Generator - F Terminal
Control Circuit parameter. The Generator - F Terminal Control
Circuit parameter should display between 5-95% depending on the
actual turned on accessories.
Circuit/System Testing
| 1. |
Verify that a test lamp
illuminates between the G13 Generator B+ output circuit terminal 1
X1 and ground. |
| ⇒ |
If the test lamp does not illuminate, test the B+
circuit for an open/high resistance. |
| 2. |
Ignition OFF, disconnect the
X2 harness connector at the G13 Generator and the appropriate
harness connector at the K20 Engine Control Module. |
| 3. |
Test for less than 5 Ω
between the X2 harness connector F-terminal and the appropriate
harness connector at the K20 Engine Control Module as listed
below: |
| |
• |
LBS or LSF - X1 terminal
77 |
| |
• |
LDE or LLU - X2 terminal
21 |
| ⇒ |
If not the specified value, test the F-terminal
circuit for an high/open resistance |
| 4. |
Test for infinite resistance
between the G13 Generator harness connector F-terminal and
ground. |
| ⇒ |
If less than the specified range, test for short
to ground or a short to voltage |
| 5. |
Connect the harness connector
at the K20 Engine Control Module. |
| 6. |
Adapt the G13 Generator
L-terminal to the X2 harness connector L-terminal. |
| 7. |
Engine run at 2 500 RPM,
verify the battery voltage is 12.6-15 V. |
| ⇒ |
If not the specified value, refer to
Charging System Test . If the circuit tests normal, test the
G13 Generator before replacing. |
| 8. |
If the circuit tests normal,
replace the K20 Engine Control Module. |
Component Testing
Dynamic Test
| 1. |
Connect a oscilloscope at the
G13 Generator terminal B+ X1 and the G13 Generator generator
housing. |
| 2. |
Engine run at 2 500
RPM. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
