HOLDEN GEN III V8, Service Training

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GEN III V8 ENGINE MANAGEMENT
The oxygen sensors are mounted in the exhaust
pipes and are referred to as Bank 1 Sensor 1 (left
exhaust pipe) Bank 2 Sensor 1 (right exhaust pipe)
The following DTCs set when the PCM detects a
H02S signal circuit that is low
DTC P0131 Bank 1 Sensor 1 H02S
DTC P0151 Bank 2 Sensor 1 H02S
The following DTCs set when the PCM detects a
H02S signal circuit that is high
DTC P0132 Bank 1 Sensor 1 H02S
DTC P0152 Bank 2 Sensor 1 H02S
The following DTCs set when the PCM detects no
H02S activity
DTC P0134 Bank 1 Sensor 1 H02S
DTC P0154 Bank 2 Sensor 1 H02S
A fault in the oxygen sensor heater element or its
ignition feed or earth results in an increase in time to
Closed Loop fuel control This may cause increased
emissions, especially at start-up The following
DTCs set when the PCM detects a malfunction in
the H02S heater circuits
• DTC P0135 Bank 1 Sensor 1 H02S heater
• DTC P0155 Bank 2 Sensor 1 H02S heater
Response Time
Not only is it necessary for the oxygen sensors to
produce voltage signals for rich or lean exhaust, it is
also important to respond quickly to changes If the
oxygen sensors respond slowly, the customer may
complain of poor fuel economy, rough idle, surging
or lack of performance The PCM will set a DTC that
indicates degraded H02S performance if a H02S
response switching, transition time, or ratio problem
is detected
DTC P 1 1 3 3 Insufficient Switching Bank 1 Sensor 1
DTC P 1 1 3 4 Transition Time Ratio Bank 1 Sensor 1
DTC P 1 1 5 3 Insufficient Switching Bank 2 Sensor 1
DTC P 1 1 5 4 Transition Time Ratio Bank 2 Sensor 1
Oxygen Sensor Contaminants
Carbon
Black carbon or soot deposits result from over-rich
air-fuel mixtures However, carbon does not harm an
oxygen sensor Deposits can be burned off in the
vehicle by running the engine at part throttle for at
least two minutes
Silica
Certain RTV silicon gasket materials give off vapour
as they cure that may contaminate the oxygen
sensor This contamination is usually caused by the
vapours being pulled from the PCV system, into the
combustion chamber and passed on to the exhaust
system The sand like particles from the RTV silica
embed in the molecules of the oxygen sensor
element and plug up the surface With the outside of
the oxygen sensor element not able to sense all of
the oxygen in the exhaust system it results in lazy
oxygen sensor response and engine control The
oxygen sensor will have a whitish appearance on
the outside if it has been contaminated
There is also a possibility of silica contamination
caused by silicon in the fuel Some oil companies
have used silicone to raise the octane rating of their
fuel Careless fuel handling practices with transport
containers can result in unacceptable concentrations
of silicone in the fuel at the pump
Silica contamination can be caused by silicon in
lubricants used to install vacuum hoses on fittings
Do not use silicon sealers on gaskets or exhaust
joints
Lead
Lead glazing of the sensors can be introduced when
regular, or leaded fuel is burned It is difficult to
detect lead contamination by visual inspection
Other Substances
Oil deposits will ultimately prevent oxygen sensor
operation The sensor will have a dark brown
appearance Causes of high oil consumption should
be checked
The additives in ethylene glycol can also affect
oxygen sensor performance This produces a
whitish appearance If antifreeze enters the exhaust
system, you will likely encounter other, more
obvious, symptoms of cooling system trouble If for
example the engine had a head gasket failure where
coolant did enter the combustion chamber it would
be a good idea to check the oxygen sensor
operation after the head gasket was repaired
Multiple Failures
If you encounter multiple or repeated oxygen sensor
failures on the same vehicle, consider
contamination
Leaded fuel, silica contamination from uncured, low-
grade (unapproved) RTV sealant, and high oil
consumption are possible causes
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