P1401
Reference Data:
Component Description
The EGR temperature sensor detects temperature changes in the EGR passageway. When the EGR volume control valve opens, hot exhaust gases flow, and the temperature in the passageway changes. The EGR temperature sensor is a thermistor that modifies a voltage signal sent from the ECM. This modified signal then returns to the ECM as an input signal. As the temperature increases, EGR temperature sensor resistance decreases.
This sensor is not directly used to control the engine system. It is used only for the on board diagnosis.
CAUTION: Do not use ECM ground terminals when measuring input/output voltage.
Doing so may lead the ECM's transistor damage. Use ground other than ECM, such as body ground.
When EGR system is operating.
Voltage: 0 - 1.5 V
On Board Diagnosis Logic
Malfunction is detected when (Malfunction A) an excessively low voltage from the EGR temperature sensor is sent to ECM even when engine coolant temperature is low. (Malfunction B) an excessively high voltage from the EGR temperature sensor is sent to ECM even when engine coolant temperature is high.
Possible Cause
MALFUNCTION A
- Harness or connectors (The EGR temperature sensor circuit is shorted.)
- EGR temperature sensor
- Malfunction of EGR function
MALFUNCTION B
- Harness or connectors (The EGR temperature sensor circuit is open.)
- EGR temperature sensor
- Malfunction of EGR function
DTC Confirmation Procedure
Perform "PROCEDURE FOR MALFUNCTION A" first. If 1st trip DTC cannot be confirmed, perform "PROCEDURE FOR MALFUNCTION B".
NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.
PROCEDURE FOR MALFUNCTION A
With CONSULT-II
1. Turn ignition switch "ON".
2. Select "DATA MONITOR" mode with CONSULT-II.
3. Verify that "COOLAN TEMP/S" is less than 50 °C (122 °F).
If the engine coolant temperature is above the range, cool the engine down.
4. Start engine and let it idle for at least 8 seconds.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
With GST
Follow the procedure "With CONSULT-II" above.
PROCEDURE FOR MALFUNCTION B
CAUTION: Always drive vehicle at a safe speed.
TESTING CONDITION:
Always perform the test at a temperature above -10 °C (14 °F).
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select "EGR VOL CONT/V" in "ACTIVE TEST" mode with CONSULT-II.
3. Hold engine speed at 1,500 rpm.
4. Touch "Qu" and set the EGR volume control valve opening to 50 step and check EGR TEMP SEN.
EGR TEMP SEN should decrease to less than 1.0 V.
If the check result is NG, go to "Diagnostic Procedure" below.
If the check result is OK, go to the following step.
5. Turn ignition switch "OFF" and wait at least 5 seconds then turn "ON".
6. Check the output voltage of "THRTL POS SEN" (at closed throttle position) and note it.
7. Start engine and maintain the following conditions for at least 5 consecutive seconds.
8. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
With GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 10 seconds, then turn "ON".
3. Select "MODE 1" with GST and maintain the following conditions for at least 5 consecutive seconds.
4. Select "MODE 7" with GST.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.
EC-EGR/TS-01:
EC-EGR/TS-01 Connector View:
Wiring Diagram
Diagnostic Procedure
Diagnostic Procedure Steps 1 - 3:
Diagnostic Procedure Steps 4 - 5:
