Workshop Manuals Factory service & repair Vauxhall
Vauxhall Astra J11 · Engine
11 · Engine

DTC P0621

Make
Vauxhall
Model
Astra J
Section
Engine Electrical › Other Information › DTC P0621
EngineDTC P0621

DTC P0621

Diagnostic Instructions

•  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
•  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
•  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0621: Generator L-Terminal Circuit

Diagnostic Fault Information



Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

B+
P0622, P0625
P0621, 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 turn ON control circuit to control the load of the generator on the engine. A high side driver in the ECM applies a voltage to the voltage regulator. This controls the voltage regulator to turn the field circuit ON and OFF. The ECM monitors the state of the generator turn ON control circuit. The ECM should detect low voltage on generator turn on control circuit when the ignition is ON and the engine is OFF, or when the charging system malfunctions. With the engine running, the ECM should detect high voltage on the generator turn on control circuit.

Conditions for Running the DTC

•  The ignition ON, engine OFF for ignition on test.
•  The engine is running for the run test.

Conditions for Setting the DTC

•  During the ignition on test, the ECM detects voltage on the generator turn on control circuit for 5 s.
•  During the run test, the ECM detects low voltage on the generator turn on control circuit for 15 s.

Action Taken When the DTC Sets

DTC P0621 is a C type DTC.

Conditions for Clearing the DTC

DTC P0621 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 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 L-terminal and the appropriate harness connector at the K20 Engine Control Module as listed below:
  •  LBS or LSF - X1 terminal 21
  •  LDE or LLU - X2 terminal 1
  •  LPL - X2 terminal 81
⇒ If not the specified value, test the L-terminal circuit for an high/open resistance.
4. Test for infinite resistance between the G13 Generator harness connector L-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 F-terminal to the X2 harness connector F-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.
3. Compare the pictured signal with the following references Generator Oscilloscope Information .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•  Control Module References for ECM replacement, setup and programming

Parts & tools for this job For Vauxhall Astra

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