СИСТЕМА ECD - Air Conditioning Signal Circuit
DESCRIPTION
When the A/C compressor is on, the A/C amplifier sends the A/C signal to the ECM and the ECM increases the fuel injection volume to improve driveability during engine idling.
WIRING DIAGRAM
INSPECTION PROCEDURE
When using intelligent tester:
| 1.READ VALUE USING INTELLIGENT TESTER (AIR CONDITIONING SIGNAL) |
Connect the intelligent tester to the DLC3.
Enter the following menus: Powertrain / Engine and ECT / Data List / A/C SIG.
- Result:
| Switch Condition | A/C SIG |
| A/C switch off | OFF |
| A/C switch on | ON |
| OK | |
| |
| PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
|
|
| 2.CHECK ECM (AC1 VOLTAGE) |
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G62-2 (AC1) - Body ground | A/C switch on | Below 1.5 V |
| G62-2 (AC1) - Body ground | A/C switch off | 7.5 to 14 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| 3.CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONING AMPLIFIER) |
Disconnect the A/C amplifier connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| G25-17 (AC1) - G62-2 (AC1) | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
| Tester Connection | Condition | Specified Condition |
| G25-17 (AC1) or G62-2 (AC1) - Body ground | Always | 10 kΩ or higher |
Reconnect the A/C amplifier connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK | |
| |
| REPLACE AIR CONDITIONING AMPLIFIER
|
|
When not using intelligent tester:
| 1.CHECK ECM (AC1 VOLTAGE) |
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
| G62-2 (AC1) - Body ground | A/C switch on | Below 1.5 V |
| G62-2 (AC1) - Body ground | A/C switch off | 7.5 to 14 V |
Text in Illustration| *a | Component with harness connected
(ECM) |
| OK | |
| |
| PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
|
|
| 2.CHECK HARNESS AND CONNECTOR (ECM - AIR CONDITIONING AMPLIFIER) |
Disconnect the A/C amplifier connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| G25-17 (AC1) - G62-2 (AC1) | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
| Tester Connection | Condition | Specified Condition |
| G25-17 (AC1) or G62-2 (AC1) - Body ground | Always | 10 kΩ or higher |
Reconnect the A/C amplifier connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK | |
| |
| REPLACE AIR CONDITIONING AMPLIFIER
|
|
