SEAT Workshop Service and Repair Manuals > Leon Mk2 > Power unit | 4 cyl. diesel engine with distributor pump | Fuel preparation system Diesel injection | Components and functions: checking | Coolant temperature sender: checking

Checking process

–	Connect fault reader -V.A.G 1551- (-V.A.G 1552-). Start engine and select “Address code” 01 to select engine control unit.

Indicated on display:

–	Press keys 0 and 8 for the function “Read measured value block” and confirm entry with Q key.

Rapid data transfer                 HELP

Select function XX

Indicated on display:

–	Press keys 0, 0 and 1 for “Display group number 1” and confirm entry with Q key.

Read measured value block

Enter number group values XXX

–

–	Indicated on display:

–	Consult coolant temperature value in display field 4. The value should increase uniformly and without interruption.

–	In the case of a fault, replacement values are displayed for the fuel temperature or the value -4.5 °C.

–	If no realistic value is given in field 4 or if replacement values are displayed for the fuel temperature or 5.4 °C, the coolant temperature sender and the wiring to the sender should be checked as follows:

–	Press → key.

–	Press keys 0 and 6 for the “End output” function and confirm input with the Q key.

–	Switch off ignition.

Read measured value block      1       →

900/min    3.8 mg    1,720 V     76.2 °C

–	Extract the connector -1- for the coolant temperature sender -G62- Components' fitting locations, → Chapter.

–	Connect the manual multimetre between the two contacts of the sender -2- for the coolant temperature -G62-.

Specification: see diagram

Scale A shows resistance values for temperature range 0...50 °C, and scale B the values for temperature range 50...100 °C.

Examples:

t	30 °C corresponds to a resistance of 1,500...2,000 Ω

t	80 °C corresponds to a resistance of 275...375 Ω

If the specification is not obtained:

–	Renew coolant temperature sender -G62-.

If the specification is obtained:

–	Connect test box -V.A.G 1598/31- to control unit wiring harness. The engine control unit remains disconnected.

–	Check the wiring between test box and 2-pin connector for open circuit using current flow diagram. Contact 1+socket 112 Contact 2+socket 104 Wire resistance: 1,5 Ω Max.

–	Additionally check wires for shorts to one another, to vehicle earth or to battery positive. Specification: ∞ Ω

If no wiring fault is detected:

–	Replace diesel direct injection control unit -J248- → Anchor.

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