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Page 1064 of 2100
6E±97
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Starter Control System Check
StepNo Ye s Value(s) Action
31. Gear position is ªpark or neutralº.
2. Do not depress the accelerator pedal.
3. Turn the key to ªSTARTº position.
4. Release the key switch to the to ªONº position.
Does the engine crank?
ÐGo to Step 27Go to Step 4
41. Install the Tech 2.
2. Select ªDisplay DTCsº with the Tech 2.
Are any DTCs stored?
ÐGo to Step 5Go to Step 6
5Review and record for Tech 2 Failure Records data and
DTCs.
Were any DTCs information stored?
Ð
Go to DTCs
Chart
Ð
61. Gear position is ªpark or neutralº.
2. Do not depress the accelerator pedal.
3. Turn the key to ªSTARTº position.
Is the engine cranking?
ÐGo to Step 27Go to Step 7
7Check the anti±theft module circuit. Check the circuit
between PCM and anti±theft module.
Is the problem found?
ÐGo to Step 8Go to Step 9
8Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
91. Probe the anti-theft module circuit to GND.
2. Turn the key to ªSTARTº position.
Is the engine cranking?
ÐGo to Step 10Go to Step 11
10Check the anti-theft system. Refer to section 8H
anti-theft.
ÐVerify repairÐ
11Check the starter relay, starter fuse and engine fuse.
Is the problem found?
Go to Step 12Go to Step 13
12Replace the starter relay, starter fuse and engine fuse.
Is the action complete?
ÐVerify repairÐ
13Check the starter circuit.
1. Ignition is ºOFFº.
2. Remove the starter relay.
3. Check the circuit between starter relay and starter
motor.
Is the problem found?
ÐGo to Step 14Go to Step 15
14Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
15Check the starter circuit.
1. Remove the main fuse (100A).
2. Check the circuit between main fuse and starter
motor.
3. Check the circuit between GND and starter motor.
Is the problem found?
ÐGo to Step 16Go to Step 17
Page 1065 of 2100
6E±98
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Starter Control System Check
StepNo Ye s Value(s) Action
16Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
17Check the starter signal circuit.
1. Remove the starter fuse (10A).
2. Disconnect the PCM.
3. Check the circuit between Powertrain Control
module (PCM) and starter fuse.
Is the problem found?
ÐGo to Step 18Go to Step 19
18Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
19Check the ªpark or neutralº signal circuit.
1. Remove the starter relay.
2. Disconnect the PCM.
3. Check the circuit between PCM and starter relay.
Is the problem found?
ÐGo to Step 20Go to Step 21
20Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
21Check the ªpark or neutralº signal circuit.
1. Remove the starter relay.
2. Disconnect the MODE switch.
3. Remove the engine (15A) fuse and back up (15A)
fuse.
4. Check the circuit between MODE switch and starter
relay.
5. Check the circuit between MODE switch and engine
fuse.
6. Check the circuit between MODE switch and PCM.
7. Check the circuit between MODE switch and back
up fuse.
Is the problem found?
ÐGo to Step 22Go to Step 23
22Repair the circuit as necessary.
Is the action complete?
ÐVerify repairÐ
23Check the MODE switch. Refer to 4L30E Automatic
transmission.
Is the problem found?Go to Step 24Go to Step 25
24Replace the MODE switch.
Is the action complete?
ÐVerify repairÐ
25Check the starter motor. Refer to Section 6D Engine
Electrical.
Is the problem found?Go to Step 26Go to Step 28
26Replace the starter motor.
Is the action complete?
ÐVerify repairÐ
Page 1069 of 2100
6E±102
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Circuit Description
The electronic Ignition system uses a coil -at-plug method
of spark distribution. In this type of ignition system, the
powertrain control module (PCM) triggers the correct
driver outside the Ignition Current Sense System (ICSS),
which then triggers the correct ignition coil based on the
58X signal received from the crankshaft position sensor
(CKP). The spark plug connected to the coil fires when
the ICSS opens the ground circuit for the coil's primary
circuit.
During crank, the PCM monitors the CKP 58X signal. The
CKP signal is used to determine which cylinder will fire
first. After the CKP 58X signal has been processed by the
PCM, it will command all six injectors to allow a priming
shot of fuel for all the cylinders. After the priming, the
injectors are left ªOFFº during the next six 58X reference
pulses from the CKP. This allows each cylinder a chance
to use the fuel from the priming shot. During this waiting
been received by the PCM. The ION sensor signal allows
the PCM to operate the injectors sequentially based on
camshaft position. If the camshaft position signal is not
present at start - up, the PCM will begin sequential fuel
delivery with a 1 -in-6 chance that fuel delivery is correct.
The engine will run without a ION sensor signal, but will
set a DTC code.
Diagnostic Aids
An intermittent problem may be caused by a poor
connection, rubbed - through wire insulation or a wire
broken inside the insulation. Check for the following
items:
Poor connection or damaged harness-Inspect the
PCM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.
Faulty engine coolant temperature sensor-Using a
Tech 2, compare engine coolant temperature with
intake air temperature on a completely cool engine.
Engine coolant temperature should be within 10 C of
intake air temperature. If not, replace the ECT sensor.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
5. An obvious cause of low fuel pressure would be an
empty fuel tank.
6. The engine will easily start and run if a few injectors
are disabled. It is not necessary to test all injectors
at this time since this step is only a test to verify that
all of the injectors have not been disabled by fuel
contamination.
7. A blinking test light verifies that the PCM is
monitoring the 58X crankshaft reference signal and
is capable of activating the injectors. If there is an
open or shorted driver circuit, DTCs 201 ± 206 and
a misfire DTC 300 ± 306 should be set.
19. By using a spark tester, each ignition coil's ability to
produce 25,000 volts is verified.
25. If there is an open or shorted driver circuit, DTCs
201 ± 206 and a misfire DTC 301 ± 306 should be
set. All six injector driver circuits can be checked at
one time without removing the intake manifold if a J
39021 ± 95 test light is available. This is the
alternative procedure:
With the ignition ªOFFº, disconnect the gray
connector located at the rear of the air filter, attached
to a bracket on the purge canister.
Connect test light J 39021 ± 95 to the connector. Do
any of the light constantly illuminate or fail to blink
when the engine is cranked? If so, repair the short or
open circuit, or replace the PCM if indicated.
This procedure only tests the driver circuit as far as the
test connection, so step 31 is added to test the circuit all
the way to the injector.
Engine Cranks But Will Not Run
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Check the ignition coil fuse, the engine fuse, and the
PCM fuse.
Was a fuse blown?
ÐGo to Step 3Go to Step 4
3Check for a short to ground and replace the fuse.
Is the action complete?
ÐVerify repairÐ
Page 1077 of 2100
6E±110
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Fuel System Electrical Test
StepNo Ye s Value(s) Action
11Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ
121. Reconnect the fuel pump relay.
2. Disconnect the fuel pump electrical connector at the
fuel tank.
3. Using a test light connected to ground, probe the
fuel pump feed wire (harness side).
4. Command the fuel pump ªONº with a Tech 2.
Did the light illuminate for 2 seconds?
ÐGo to Step 15Go to Step 13
131. Honk the horn to verify that the horn relay is
functioning.
2. Substitute the horn relay for the fuel pump relay.
3. Leave the test light connected as in step 12.
4. Command the fuel pump ªONº with the Tech 2.
Did the test light illuminate for 2 seconds when the fuel
pump was commanded ªONº?
ÐGo to Step 17Go to Step 14
141. Re-connect the horn relay in its proper location.
2. Check for a short circuit, blown fuse or open circuit
between the relay and the fuel tank.
Is the action complete?
ÐVerify repairÐ
151. With the fuel pump electrical connector at the fuel
tank disconnected, connect a test light between the
feed wire and the ground wire (harness side).
2. Command the fuel pump ªONº with a Tech 2.
Did the test light illuminate for 2 seconds?
ÐGo to Step 18Go to Step 16
16Repair the open circuit in the fuel pump ground wire.
Is the action complete?
ÐVerify repairÐ
171. Re-connect the horn relay in its proper location.
2. Replace the fuel pump relay.
Is the action complete?
ÐVerify repairÐ
18Replace the fuel pump.
Is the action complete?
ÐVerify repairÐ
Page 1083 of 2100
6E±116
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Circuit Description
When the ignition switch is turned ªONº, the powertrain
control module (PCM) will turn ªONº the in-tank fuel
pump. The in-tank fuel pump will remain ªONº as long as
the engine is cranking or running and the PCM is receiving
58X crankshaft position pulses. If there are no 58X
crankshaft position pulses, the PCM will turn the in-tank
fuel pump ªOFFº 2 seconds after the ignition switch is
turned ªONº or 2 seconds after the engine stops running.
The in-tank fuel pump is an electric pump within an
integral reservoir. The in-tank fuel pump supplies fuel
through an in-line fuel filter to the fuel rail assembly. The
fuel pump is designed to provide fuel at a pressure above
the pressure needed by the fuel injectors. A fuel pressure
regulator, attached to the fuel rail, keeps the fuel available
to the fuel injectors at a regulated pressure. Unused fuel
is returned to the fuel tank by a separate fuel return line.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Connect the fuel pressure gauge to the fuel feed line
as shown in the fuel system illustration. Wrap a
shop towel around the fuel pressure connection in
order to absorb any fuel leakage that may occur
when installing the fuel pressure gauge. With the
ignition switch ªONº and the fuel pump running, the
fuel pressure indicated by the fuel pressure gauge
should be 333-376 kPa (48-55 psi). This pressure
is controlled by the amount of pressure the spring
inside the fuel pressure regulator can provide.
3. A fuel system that cannot maintain a constant fuel
pressure has a leak in one or more of the following
areas:
The fuel pump check valve.
The fuel pump flex line.
The valve or valve seat within the fuel pressure
regulator.
The fuel injector(s).
4. Fuel pressure that drops off during acceleration,
cruise, or hard cornering may case a lean condition.
A lean condition can cause a loss of power, surging,
or misfire. A lean condition can be diagnosed using
a Tech 2. If an extremely lean condition occurs, the
oxygen sensor(s) will stop toggling. The oxygen
sensor output voltage(s) will drop below 500 mV.
Also, the fuel injector pulse width will increase.
IMPORTANT:Make sure the fuel system is not
operating in the ªFuel Cut-Off Modeº.
When the engine is at idle, the manifold pressure is
low (high vacuum). This low pressure (high vacuum)
is applied to the fuel pressure regulator diaphragm.
The low pressure (high vacuum) will offset the
pressure being applied to the fuel pressure regulator
diaphragm by the spring inside the fuel pressure
regulator. When this happens, the result is lower fuel
pressure. The fuel pressure at idle will vary slightly as
the barometric pressure changes, but the fuel
pressure at idle should always be less than the fuel
pressure noted in step 2 with the engine ªOFFº.16.Check the spark plug associated with a particular
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. If
checking the spark plug associated with a particular
fuel injector for fouling or saturation does not
determine that a particular fuel injector is leaking,
use the following procedure:
Remove the fuel rail, but leave the fuel lines and
injectors connected to the fuel rail. Refer to
Fuel Rail
Assembly
in On-Vehicle Service.
Lift the fuel rail just enough to leave the fuel injector
nozzles in the fuel injector ports.
CAUTION: In order to reduce the risk of fire and
personal injury that may result from fuel spraying on
the engine, verify that the fuel rail is positioned over
the fuel injector ports and verify that the fuel injector
retaining clips are intact.
Pressurize the fuel system by connecting a 10 amp
fused jumper between B+ and the fuel pump relay
connector.
Visually and physically inspect the fuel injector
nozzles for leaks.
17.A rich condition may result from the fuel pressure
being above 376 kPa (55 psi). A rich condition may
cause a DTC P0132 or a DTC P0172 to set.
Driveability conditions associated with rich
conditions can include hard starting (followed by
black smoke) and a strong sulfur smell in the
exhaust.
20.This test determines if the high fuel pressure is due
to a restricted fuel return line or if the high fuel
pressure is due to a faulty fuel pressure regulator.
21.A lean condition may result from fuel pressure
below 333 kPa (48 psi). A lean condition may
cause a DTC P0131 or a DTC P0171 to set.
Driveability conditions associated with lean
conditions can include hard starting (when the
engine is cold ), hesitation, poor driveability, lack of
power, surging , and misfiring.
22.Restricting the fuel return line causes the fuel
pressure to rise above the regulated fuel pressure.
Command the fuel pump ªONº with the Tech 2. The
fuel pressure should rise above 376 kPa (55 psi) as
the fuel return line becomes partially closed.
NOTE: Do not allow the fuel pressure to exceed 414 kPa
(60 psi). Fuel pressure in excess of 414 kPa (60 psi) may
damage the fuel pressure regulator.
CAUTION: To reduce the risk of fire and personal
injury:
It is necessary to relieve fuel system pressure
before connecting a fuel pressure gauge. Refer to
Fuel Pressure Relief Procedure, below.
A small amount of fuel may be released when
disconnecting the fuel lines. Cover fuel line
fittings with a shop towel before disconnecting, to
catch any fuel that may leak out. Place the towel in
an approved container when the procedure is
completed.
Page 1147 of 2100
6E±180
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
ECT display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor. A change
in the display will indicate the location of the fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.2. The HO2S should be allowed to cool before
performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.
4. Ensures that the ignition feed circuit to the HO2S is
not open or shorted. The test light should be
connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.
5. Checks the HO2S heater ground circuit.
6. Checks or an open or shorted HO2S heater element.
10.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0135 ± HO2S Heater Circuit Bank 1 Sensor 1
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2NOTE: If the engine has just been operating ,allow the
engine to cool for at least 15 minutes before
proceeding.
1. Remove the fuel pump relay.
2. Connect a fused jumper at the fuel pump relay
socket, between the battery positive at the relay and
the relay wire that leads to the fuel pump and HO2S
fuses.
3. Ignition ªOFFº.
4. Install a Tech 2.
5. Ignition ªONº, engine ªOFFº.
6. Monitor the Bank 1 HO2S 1 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified values?
Above
650 mV or
below
250 mV
Refer to
Diagnostic
Aids
Go to Step 3
3Inspect the fuse for the Bank 1 HO2S 1 ignition feed.
Is the fuse open?
ÐGo to Step 15Go to Step 4
41. Ignition ªOFFº.
2. Raise the vehicle.
3. Disconnect the Bank 1 HO2S 1 electrical connector.
4. Using a test light connected to a good ground (do
not use Bank 1 HO2S 1 heater ground or Bank 1
HO2S 1 low), probe the ignition feed circuit at the
Bank 1 HO2S 1 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between the Bank 1 HO2S 1
ignition feed and the Bank 1 HO2S 1 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8
Page 1148 of 2100
6E±181
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0135 ± HO2S Heater Circuit Bank 1 Sensor 1
StepNo Ye s Value(s) Action
61. Allow the HO2S to cool for at least 15 minutes.
2. Using a DVM, measure the resistance between the
Bank 1 HO2S 1 ignition feed and the Bank 1 HO2S 1
heater ground at the Bank 1 HO2S 1 pigtail.
Is the HO2S heater resistance within the specified
values?
3-6 ohmsGo to Step 9Go to Step 10
7Repair the open Bank 1 HO2S 1 ignition feed circuit to
Bank 1 HO2S 1.
Is the action complete?
ÐVerify repairÐ
8Repair the open Bank 1 HO2S 1 heater ground circuit
to Bank 1 HO2S 1.
Is the action complete?
ÐVerify repairÐ
91. Check for a poor connection at the Bank 1 HO2S 1
harness terminals.
2. If a poor connection is found, replace terminals.
Was a poor connection found?
ÐVerify repairGo to Step 10
10Check for a poor Bank 1 HO2S 1 high or low circuit
terminal connection at the Bank 1 HO2S 1 harness
connector and replace terminal(s) if necessary.
Did any terminals require replacement?
ÐVerify repairGo to Step 11
111. Ignition ªOFFº.
2. Disconnect the PCM and check the continuity of the
Bank 1 HO2S 1 signal circuit and the Bank 1 HO2S
1 low circuit.
3. If the Bank 1 HO2S 1 high circuit or HO2S low circuit
measures over 5 ohms, repair open or poor
connection as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
12Check for a poor Bank 1 HO2S 1 low circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 13
13Check for a poor Bank 1 HO2S 1 high circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 14
14Replace the Bank 1 HO2S 1.
Is the action complete?
ÐVerify repairÐ
15Locate and repair the short to ground in Bank 1 HO2S 1
ignition feed circuit and replace the fault fuse.
Is the action complete?
ÐVerify repairÐ
Page 1159 of 2100
6E±192
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
display on the Tech 2 while moving connectors and
wiring harnesses related to the sensor. A change in the
display will indicate the location of the fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.2. The HO2S should be allowed to cool before
performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.
4. This ensures that the ignition feed circuit to the
HO2S is not open or shorted. The test light should
be connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.
5. This checks the HO2S heater ground circuit.
6. This checks for an open or shorted HO2S heater
element.
11.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0141 ± HO2S Heater Circuit Bank 1 Sensor 2
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2NOTE: If the engine has just been operating, allow the
engine to cool for at least 15 minutes before
proceeding.
1. Remove the fuel pump relay.
2. Connect a fused jumper at the fuel pump relay
socket, between the battery positive at the relay and
the relay wire that leads to the fuel pump and HO2S
fuses.
3. Ignition ªOFFº.
4. Install a Tech 2.
5. Ignition ªONº, engine ªOFFº.
6. Monitor the Bank 1 HO2S 2 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified values?
Above
650 mV or
below
250 mV
Refer to
Diagnostic
Aids
Go to Step 3
3Inspect the fuse for Bank 1 HO2S 2 ignition feed.
Is the fuse open?
ÐGo to Step 15Go to Step 4
41. Ignition ªOFFº.
2. Raise the vehicle.
3. Disconnect the Bank 1 HO2S 2 electrical connector.
4. Using a test light connected to a good ground (do
not use Bank 1 HO2S 2 heater ground or Bank 1
HO2S 2 low), probe the ignition feed circuit at the
Bank 1 HO2S 2 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between the Bank 1 HO2S 2
ignition feed and the Bank 1 HO2S 2 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8
Page 1160 of 2100
6E±193
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0141 ± HO2S Heater Circuit Bank 1 Sensor 2
StepNo Ye s Value(s) Action
61. Allow the HO2S to cool for at least 15 minutes.
2. Using a DVM, measure the resistance between the
Bank 1 HO2S 2 ignition feed and the Bank 1 HO2S 2
heater ground at the Bank 1 HO2S 2 pigtail.
Is the HO2S resistance within the specified values?
3-6 ohmsGo to Step 9Go to Step 10
7Repair the open Bank 1 HO2S 2 ignition feed circuit to
Bank 1 HO2S 2.
Is the action complete?
ÐVerify repairÐ
8Repair the open Bank 1 HO2S 2 heater ground circuit.
Is the action complete?
ÐVerify repairÐ
91. Check for a poor connection at the Bank 1 HO2S 2
harness terminals.
2. If a poor connection is found, replace the terminals.
Was a poor connection found?
ÐVerify repairGo to Step 10
101. Ignition ªOFFº.
2. Disconnect the PCM and check the continuity of the
Bank 1 HO2S 2 signal circuit and the Bank 1 HO2S
2 low circuit.
3. If the Bank 1 HO2S 2 signal circuit or the HO2S low
circuit measures over 5 ohms, repair the open or
poor connection as necessary.
Was a problem found?
ÐVerify repair Go to Step 11
111. Ignition ªOFFº.
2. Disconnect the PCM and check the continuity of the
Bank 1 HO2S 1 signal circuit and the Bank 1 HO2S
1 low circuit.
3. If the Bank 1 HO2S 1 high circuit or the HO2S low
circuit measures over 5 ohms, repair the open or
poor connection as necessary.
Was a problem found?
ÐVerify repairGo to Step 12
12Check for a poor Bank 1 HO2S 2 low circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 13
13Check for a poor Bank 1 HO2S 2 high circuit terminal
connection at the PCM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 14
14Replace Bank 1 HO2S 2.
Is the action complete?
ÐVerify repairÐ
15Locate and repair the short to ground in Bank 1 HO2S 2
ignition feed circuit and replace the faulty fuse.
Is the action complete?
ÐVerify repairÐ
Page 1175 of 2100
6E±208
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
display on the Tech 2 while moving connectors and
wiring harnesses related to the sensor. A change in the
display will indicate the location of the fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.2. The HO2S should be allowed to cool before
performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.
4. Ensures that the ignition feed circuit to the HO2S is
not open or shorted. The test light should be
connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.
5. Checks the HO2S heater ground circuit.
6. Checks for an open or shorted HO2S heater
element.
10.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
DTC P0155 ± HO2S Heater Circuit Open Bank 2 Sensor 1
StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2NOTE: If the engine has just been operating, allow the
engine to cool for at least 15 minutes before
proceeding.
1. Remove the fuel pump relay.
2. Connect a fused jumper at the fuel pump relay
socket, between the battery positive at the relay and
the relay wire that leads to the fuel pump and HO2S
fuses.
3. Ignition ªOFFº.
4. Install a Tech 2.
5. Ignition ªONº, engine ªOFFº.
6. Monitor the Bank 1 HO2S 1 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified value?
Above
650 mV or
below
250 mV
Refer to
Diagnostic
Aids
Go to Step 3
3Inspect the fuse for the Bank 2 HO2S 1 ignition feed.
Is the fuse open?
ÐGo to Step 15Go to Step 4
41. Ignition ªOFFº.
2. Raise the vehicle.
3. Disconnect the Bank 2 HO2S 1 electrical connector.
4. Using a test light connected to a known good ground
(do not use Bank 2 HO2S 1 heater ground or Bank 2
HO2S 1 low), probe the ignition feed circuit at the
Bank 2 HO2S 1 electrical connector (PCM harness
side).
Does the test light illuminate?
ÐGo to Step 5Go to Step 7
5Connect the test light between Bank 2 HO2S 1 ignition
feed and Bank 2 HO2S 1 heater ground.
Does the test light illuminate?
ÐGo to Step 6Go to Step 8