Vauxhall Workshop Service and Repair Manuals

No.

TECH 1 Display

Conditions for Checking

Nominal Value

Trouble Codes

Terminal

28

AIR / FUEL RATIO

Engine running at idle speed, operating temperature

Switch off all consumers

Alternately LEAN and RICH

13, 38, 39

7, 25, 19, 36

Note:   The heating voltage for the oxygen sensor (ground control) is switched via Ter. 36 of control unit K69.

              The oxygen sensor is supplied with + 5 V and is connected between Ter. 7 and Ter. 25 of the control unit.

Notes on Trouble - shooting:

Nominal Value:

Cause of Fault:

·     Ignition Off. Disconnect oxygen sensor wiring plug P32. Ignition On. Measure voltage at wiring plug on control unit side between Ter. B and Ter. D

approx. 5 V

·     Lead interruption from

       -      control unit Ter. 7 to oxygen sensor Ter. B

       -      control unit Ter. 25 to oxygen sensor Ter. D

·     Short circuit of oxygen sensor leads

       -      to ground or one another (display 0 V)

       -      to + battery voltage (display greater than 5 V)

·     Using multimeter, measure heat resistance at oxygen sensor plug (engine side) between Ter. A and Ter. C at 20 °C / 68 °F room temperature

5 ± 0.5 W

·     Heat resistor of oxygen sensor defective

Further possible faults

·     Astra - F, Vectra / Cavalier, Calibra:

       Lead interruption between fuel pump relay K68 / Ter. 87 and oxygen sensor P32 / Ter. C

       Omega - B:

       Lead interruption between reverse battery protection relay K42 / Ter. 87 and oxygen sensor P32 / Ter. C

·     Lead interruption from oxygen sensor Ter. A to control unit K69 / Ter. 36

·     Oxygen sensor P32 defective

·     Mixture constantly too rich or constantly too lean

·     Control unit K69 defective