1998 OPEL FRONTERA engine

6E–229 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0405 – EGR Low Volt
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF”, review and record
Tech 2 Failure Records Data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using Tech 2, monitor “DTC” info for DTC P0405
until the DTC P0405 test runs. Note the result.
Does Tech 2 indicates DTC P0405 failed this ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
—Go to Step 4Go to Step 5
4Repair the damaged pin or terminal.
Is the action complete?
—Verify repair—
51. Disconnect the EGR harness connector.
2. Ignition “ON”.
3. At the EGR valve, use a DVM to check the voltage
at the 5 volt reference wire (RED) and ground (B).
Did the DVM indicate the specified value?
4–6 VGo to Step 6Go to Step 7
61. Disconnect the EGR harness connector.
2. Measure resistance between terminal B and D.
Was resistance in range?
5–5.5 KGo to Step 10Go to Step 17
71. Ignition “ON”.
2. At the PCM connector, backprobe with a DVM at the
5 volt reference for the EGR valve.
Did the DVM indicate the specified value?
4–6 VGo to Step 8Go to Step 9
8Repair the open 5 volt reference circuit.
Is the action complete?
—Verify repair—
9Repair the damaged sensor ground wire.
Is the action complete?
—Verify repair—
101. Disconnect the EGR harness
2. Use an ohmmeter to measure between the pintle
position pin and the sensor ground pin on the EGR
valve.
NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.
Was the ohmmeter reading approximately equal to the
specified value?
1 to 1.25 KGo to Step 11Go to Step 17
111. Ignition “ON”.
2. Backprobe with a DVM to measure voltage at EGR
valve pintle position pin and sensor ground pin.
Was voltage in range?
Less than
0.1 V
Go to Step 17Go to Step 12

6E–230
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0405 – EGR Low Volt
StepNo Ye s Va l u e ( s ) Action
121. Ignition “ON”.
2. Backprobe with a DVM to measure voltage at PCM
sensor ground pin and pintle position pin.
Was voltage in range?
Less than
0.1 V
Go to Step 13Go to Step 18
131. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Check short circuit between EGR pintle position
circuit and EGR ground circuit.
Was any short circuit?
—Go to Step 14Go to Step 18
14Locate and repair the short to ground in the pintle
position circuit
Is the action complete?
—Verify repair—
151. Ignition “OFF”.
2. Disconnect the PCM.
3. Ignition “ON”.
4. Measure the voltage between the EGR pintle
position circuit and ground.
Is the measured voltage near the specified value?
Less than
0.1 V
Go to Step 17Go to Step 16
16Check for a short circuit between other wires and the
pintle position circuit
Was any short circuit?
—
Repair short
circuit
Verify repair
Go to Step 17
17Replace the EGR valve.
Does DTC P1404 still fail “specific DTC test on Tech 2?
—Go to Step 18Verify repair
18Examine the PCM pin and terminal connection.
Was there a damaged terminal?
—Go to Step 4Go to Step 19
19Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–231 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0406 EGR High Voltage
D06RW106
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the PCM. If current
pintle position voltage indicates more than 4.8 V and last
more than 10 seconds, then the PCM will set DTC P0406.
Conditions for Setting the DTC
Ignition voltage is between 11 and 16 volts.
EGR pintle position output voltage is more than 4.8 volt
and last more than 10 sec.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in Failure
Records data.
Conditions for Clearing the MIL/DTC
DTC P0404 can be cleared by using Tech 2 “Clear Info”
function or by disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:
Poor connection or damaged harness – Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E–232
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR High Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF”, review and record
Tech 2 Failure Records Data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using Tech 2, monitor “DTC” info for DTC P0406
until the DTC P0406 test runs. Note the result.
Does Tech 2 indicates DTC P0406 failed this ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
—Go to Step 4Go to Step 5
4Repair the damaged pin or terminal.
Is the action complete?
—Verify repair
Is the action
complete?
51. Disconnect the EGR harness connector.
2. Ignition “ON”.
3. At the EGR valve, use a DVM to check the voltage
at the 5 volt reference wire (RED).
Did the DVM indicate the specified value?
4–6 VGo to Step 8Go to Step 6
61. Ignition “ON”.
2. At the PCM connector, backprobe with a DVM at the
5 volt reference for the EGR valve.
Did the DVM indicate the specified value?
4–6 VGo to Step 7Go to Step 16
7Repair the open 5 volt reference circuit
Is the action complete?
—Verify repair—
81. Ignition “OFF”
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between D (5
V reference) and B (Sensor Ground) at EGR sensor
terminals.
NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.
Was there measured resistance in range?
5 to 5 KGo to Step 9Go to Step 15
91. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between B
and C at EGR sensor terminal.
Was there open circuit?
—Go to Step 15Go to Step 10
101. Ignition “OFF”.
2. Disconnect the EGR harness at PCM connector.
3. Use a DVM to check for shorted wire between A1
and B7.
Was there shorted wire?
—Go to Step 14Go to Step 11

6E–233 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR High Voltage
StepNo Ye s Va l u e ( s ) Action
111. Ignition “ON”.
2. Use a DVM to backprobe at terminal C of EGR
valve for voltage.
Was measured voltage more than 4.8 V?
more than
4.8 V
Go to Step 12Go to Step 12
121. Ignition “ON”.
2. Stay the EGR harness connected.
3. Check voltage by backproving at PCM B7 terminal.
Was voltage more than 4.8 V?
4.8 VGo to Step 16Go to Step 13
131. Locate short circuit at EGR harness between RED
to RED or GREEN, RED to YEL.
2. Replace EGR harness.
Is the action complete?
—Verify repair—
14Replace EGR harness.
Is the action complete?
—Verify repair—
15Replace the EGR valve.
Does DTC P1404 still fail “specific DTC test on Tech 2?
—Go to Step 16Verify repair
16Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

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
Engine is running.
Engine coolant temperature is above 60C (140F).
Engine speed is between 1800 RPM and 2500 RPM.
Throttle angle is between 10% and 40%.
Engine load is greater than 50 kPa.
MAP sensor indicates greater than 50 kPa manifold
pressure.
PCM detects no VSS signal for 12.5 seconds over a
period of 25 seconds.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
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
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
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
2Does the speedometer work?—Go to Step 10Go to Step 3
31. 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 5Go to Step 4
4Repair the sensor ground.
Is the action complete?
—Verify repair—
51. 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 7Go to Step 6
6Repair the open or short to ground which may have
blown the meter fuse.
Is the action complete?
—Verify repair—
71. 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 VGo to Step 9Go to Step 8
8Check for an open or short circuit between the
speedometer and the VSS.
Was an open or short circuit located?
—Verify repairGo to Step 9
9Replace the speedometer.
Is the action complete?
—Verify repair—

6E–236
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0502 – VSS Circuit Low Input
StepNo Ye s Va l u e ( s ) Action
101. 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 w h i l e t r a c e r ( n e x t t o t h e
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 11Go to Step 12
11Replace the VSS.
Is the action complete?
—Verify repair—
12Check for an open or short between the PCM and the
speedometer.
Was a problem found?
—Verify repairGo to Step 13
13Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—