EGR Temperature Sensor: Testing and Inspection

Exhaust gas temperature monitoring
Sensor -1-for exhaust temperature -G235and Bank 2 Exhaust Gas Temperature (EGT) Sensor 1 -G236-, testing





Special tools and equipment
^ V.A.G 1526 A
^ V.A.G 1527 B
^ V.A.G 1594 A
^ V.A.G 1598/31
^ VAS 5051 with VAS 5051/1

Test requirement:
^ Fault memory has been checked

Test sequence
- Connect vehicle diagnostic, testing and information system VAS 5051, and select vehicle system "01 - Engine electronics" from menu. When doing this engine should be idling.





Display on VAS 5051:
- Select diagnosis function "08 - Read data block" from menu -1-





Display on VAS 5051:
1 - Enter display group
- Using keypad -2-, enter "112" to select "Display group 112" and confirm entry with Q button.





Display on VAS 5051:
- Check display in display zone -1- for cylinder bank 1 (right) and in display zone 2 for cylinder bank 2 (left).
- Increase engine speed.
^ Exhaust gas temperature should increase.

- Switch off ignition.

If exhaust gas temperature readout remains constant, or if an implausible value is shown:
- Test voltage supply.
- Check wiring.

Testing voltage supply
Requirements for test:
^ Fuse for exhaust gas temperature sensor OK
Refer to Electrical Wiring Diagrams
^ Fuel pump relay OK

Note: Exhaust gas temperature sensors receive their power supply via fuel pump relay.





- Unplug brown connector -1- from Sensor -1- for exhaust temperature G235- and black connector -2- from Bank 2 Exhaust Gas Temperature (EGT) Sensor 1 -G236-.

Part 1:

Part 2:

- Connect voltage tester VAG 1527 B as follows:
- Operate starter briefly.
^ LED should light up.

If LED does not light up:
- Test for open circuit in wiring connection between Sensor -1- for exhaust temperature G235- and Bank 2 Exhaust Gas Temperature (EGT) Sensor 1 -G236- and fuel pump relay via fuse.





Checking wiring connections
- Connect test box V.A.G 1598/31 to wiring harness connectors. The engine control unit itself does not need to be connected to test box. Connect ground clamp on test box to ground -arrow-.

WARNING: To prevent damage to electronic components, switch to respective measuring range before connecting measuring cable and observe test prerequisites.





- Test for open circuit and short to positive or ground in following wiring connections:





^ Sensor -1- for exhaust temperature -G235- (cylinder bank 1 - right); brown connector





^ Bank 2 Exhaust Gas Temperature (EGT) Sensor 1 -G236- (cylinder bank 2 - left black connector

- Eliminate open circuit or short circuit using wiring diagram.

If wiring is OK
- Replace exhaust gas temperature sensor.