Opel Frontera UBS. Service manual — part 2813

8D–452

WIRING SYSTEM

2-2. Tachometer Needle Fluctuates (May Be Wide Fluctuation)

•

IS THE PULSE INPUT NORMAL?

YES

THE WAVEFORM BY OSCILLOSCOPE IS DEFORMED
(ABNORMAL INPUT)

NO

REPLACE THE METER ASSEMBLY

REPLACE THE PCM, ECM OR REPAIR A POOR
CONNECTION AT THE CONNECTORS IN THE CIRCUIT
OR A FAILURE IN THE CABLE HARNESS

2-3. Tachometer Needle Jumps Erratically

•

IS THE PULSE INPUT NORMAL?

YES

AN ABNORMAL PERIODIC WAVEFORM IS OUTPUT
BY OSCILLOSCOPE

NO

REPLACE THE METER ASSEMBLY

REPLACE THE PCM, ECM OR REPAIR A POOR
CONNECTION AT THE CONNECTORS IN THE CIRCUIT
OR A FAILURE IN THE HARNESS

WIRING SYSTEM

8D–453

I-9

Inspection of a waveform by oscilloscope

1. Check the waveform of the meter assembly connector 9 I-9 (Tachometer pulse).

Normal waveform

OV

6.7m sec.

MIN. 0.4V

MAX. 4.3V

Engine revolution : 3000 rpm

1

2

3

4

5

6

7

8

9 10 11 12 13 14

15 16 17 18 19 20 21 22

23 24 25 26 27 28 29 30

8D–454

WIRING SYSTEM

3. Voltmeter

3-1. Voltmeter Needle Does Not Move

3-2. Voltage Reading Is Too Low (Or High)

•

IS THE METER ASSEMBLY CONNECTOR I-9
SECURELY CONNECTED?

YES

•

•

•

DISCONNECT THE METER ASSEMBLY CONNECTORS I-9
TURN THE STARTER SWITCH ON
IS THE BATTERY VOLTAGE APPLIED BETWEEN THE HARNESS
SIDE CONNECTORS 15 I-9 AND 19 I-9 OF THE METER
ASSEMBLY?

YES

CONNECT THE CONNECTOR SECURELY

NO

REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT IN THE CIRCUIT BETWEEN THE
FUSE C-10 (10A) AND 15 I-9 OR THE
CONNECTORS 19 I-9 AND THE GROUND

NO

REPLACE THE METER ASSEMBLY

WIRING SYSTEM

8D–455

4. Engine Coolant Temperature (ECT) Gauge

4-1 Gauge Needle Does Not Move

•

IS THE CONNECTOR OF THE ENGINE COOLANT
TEMPERATURE UNIT CONNECTED SECURELY?

YES

•

•

•

DISCONNECT THE CONNECTOR OF THE ENGINE COOLANT
TEMPERATURE UNIT
CONNECT A 3.4W BULB BETWEEN THE HARNESS SIDE
CONNECTOR 1 E-19 OR 1 E-23 AND THE GROUND OF
THE ECT UNIT
WHEN THE STARTER SW IS TURNED ON, DOES THE
ECT GAUGE POINTER MOVE ABOUT 10 SECONDS
AFTER THAT?

YES

CONNECT THE CONNECTOR SECURELY

NO

NO

REPLACE THE ENGINE COOLANT
TEMPERATURE UNIT

•

IS THE CIRCUIT BETWEEN THE ECT GAUGE AND THE
ENGINE COOLANT TEMPERATURE UNIT NORMAL?

YES

REPLACE THE METER
ASSEMBLY

NO

REPAIR A POOR CONNECTION
AT THE CONNECTORS OR AN
OPEN CIRCUIT IN THE CIRCUIT