Opel Frontera UBS. Manual - part 332

6E–234

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0502 VSS Circuit Low Input

D06RW019

Circuit Description

The vehicle speed sensor has a magnet rotated by the
transmission output shaft.  Attached to the sensor is a hall
effect circuit the interacts with the magnetic field treated
by the rotating magnet.  A 12-volt operating supply for the
speed sensor hall circuit is supplied from the meter fuse.
The VSS pulses to ground the 9-volt signal sent from the
powertrain control module (PCM) on the reference circuit.
The PCM interprets vehicle speed by the number of
pulses to ground per second on the reference circuit.

Conditions for Setting the DTC

D

Engine is running.

D

Engine coolant temperature is above 60

°

C (140

°

F).

D

Engine speed is between 1800 RPM and 2500 RPM.

D

Throttle angle is between 10% and 40%.

D

Engine load is greater than 50 kPa.

D

MAP sensor indicates greater than 50 kPa manifold
pressure.

D

PCM detects no VSS signal for 12.5 seconds over a
period of 25 seconds.

Action Taken When the DTC Sets

D

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

D

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

D

DTC P0502 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
10. To avoid backprobing the VSS and possibly

damaging a seal or terminal, the VSS output can be
tested at the point where the transmission harness
connects to the engine harness.  Power and ground
are applied by jumpers to the VSS through the
connectors which are located just in front of the air
cleaner assembly.  The VSS signal is monitored
with a DVM as the rear driveshaft turns.  The
wheels can be turned to rotate the driveshaft, or in
2-wheels-drive vehicles the driveshaft can be turned
directly.

12. The speedometer-to-PCM VSS signal wire is

spliced to a wire leading to the cruise control
module.  If a short to ground or voltage is indicated
between the PCM and speedometer, it could be on
the cruise control circuit if the vehicle is equipped
with cruise control.

6E–235

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0502 – VSS Circuit Low Input

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

Does the speedometer work?

—

Go to 

Step 10

Go to 

Step 3

3

1. Disconnect the VSS connector.
2. Ignition “ON.”
3. Using a test light to battery +, probe the connector

ground wire.

Did the light illuminate?

—

Go to 

Step 5

Go to 

Step 4

4

Repair the sensor ground.

Is the action complete?

—

Verify repair

—

5

1. Ignition “ON,” sensor disconnected.
2. Using a DVM, measure at the VSS connector

between ground and voltage supply.

Was the measurement near the specified value?

Battery

voltage

Go to 

Step 7

Go to 

Step 6

6

Repair the open or short to ground which may have
blown the meter fuse.

Is the action complete?

—

Verify repair

—

7

1. Ignition “ON,” VSS disconnected.
2. Using a DVM, measure at the VSS connector

between ground and the wire from the
speedometer.

Was the measurement near the specified value?

7.5-8 V

Go to 

Step 9

Go to 

Step 8

8

Check for an open or short circuit between the
speedometer and the VSS.

Was an open or short circuit located?

—

Verify repair

Go to 

Step 9

9

Replace the speedometer.

Is the action complete?

—

Verify repair

—

6E–236

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0502 – VSS Circuit Low Input

  (Cont'd)

Step

No

Yes

Value(s)

Action

10

1. Ignition “OFF.”
2. Disconnect the MAF sensor and remove the air

cleaner assembly and filter element to gain access
to the 16-way black connector located immediately
to the rear of the left front headlamp.  The connector
attaches the VSS wires from the transmission
harness to the left-side engine harness.

3. Disconnect the black 16-way connector.
4. Select a terminal adapter from kit J 35616 that can

be used with a jumper to supply B+ to the blue wire
with a yellow tracer (transmission side of the
connector).

5. Use another terminal adapter to attach a voltmeter

to the light-green wire with a while tracer (next to the
wire in the previous step.)

6. Disconnect the blue connector next to the black

16-way connector, and locate the black/red tracer
wire at one corner of the blue connector.  The
black/red wire is the VSS ground.  Use a terminal
adapter to attach a jumper to ground to the
black/red VSS ground wire at the transmission side
of the blue connector.

7. Raise the rear wheels off the ground with

transmission in neutral.

Does the DVM toggle back and forth between 0.6 V and
10 V as the wheels (and driveshaft) are rotated?

—

Go to 

Step 11

Go to 

Step 12

11

Replace the VSS.

Is the action complete?

—

Verify repair

—

12

Check for an open or short between the PCM and the
speedometer.

Was a problem found?

—

Verify repair

Go to 

Step 13

13

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed.  Refer to 

UBS 98model year Immobilizer

Workshop Manual.

Is the action complete?

—

Verify repair

—

6E–237

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0562 System Voltage Low

D06RW020

Circuit Description

The powertrain control module (PCM) monitors the
system voltage on the ignition feed terminal to the PCM.
A system voltage DTC will set whenever the voltage is
below a calibrated value.

Conditions for Setting the DTC

D

Ignition “ON.”

D

System voltage is below 11.5 volts for 15 minutes.

Action Taken When the DTC Sets

D

The PCM will not illuminate the malfunction indicator
lamp (MIL).

D

The PCM will store as Failure Records conditions
which were present when the DTC was set.  This
information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

D

A history DTC P0562 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0562 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

If the DTC sets when an accessory is operated, check for
a poor connection or excessive current draw.