Page 1524 of 2490
All vehicles are fitted with a stainless steel exhaust system which features:
Low back-pressure gas flow. Catalytic converters for mark ets having unleaded fuel. Front muffler common to the left-hand and right-hand engine cylinder banks.
Downpipe Catalytic Converter Assembly
Page 1533 of 2490

Exhaust System - Exhaust System
Diagnosis and Testing
Symptom Chart
Symptom Chart
Special Tool(s)
Digital multimeter
Generic scantool
SymptomPossible SourcesAction
DTC P0420 Catalyst system efficiency below
threshold (Bank 1)Catalyst failure
Upstream O2 sensor failure
Downstream O2 sensor failure
O2 sensor heater failure
Associated harness / connector failure
*
*
*
*
*See DTC P0137, P0138
and P0140
*
DTC P0430 Catalyst system efficiency below
threshold (Bank 2)Catalyst failure
Upstream O2 sensor failure
Downstream O2 sensor failure
O2 sensor heater failure
Associated harness / connector failure
*
*
*
*
*See DTC P0157, P0158
and P0160
*
DTC P0131 O2 sensor circuit low voltage (Bank 1
sensor 1)O2 sensor failure
Sensor ground fault
Harness failure
Connector pin(s) bent, loose or corroded
*
*
*
*GO to Pinpoint Test A
*
DTC P0132 O2 sensor circuit high voltage (Bank
1 sensor 1)O2 sensor failure to B+
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. O2 sensor failure
*
*
*
*
*GO to Pinpoint Test A
*
DTC P0133 O2 sensor circuit slow response
(Bank 1 sensor 1)O2 sensor heater failure / out of spec
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. Low exhaust temperature
O2 sensor failure
*
*
*
*
*
*GO to Pinpoint Test B
*
DTC P0135 O2 sensor heater circuit malfunction
(Bank 1 sensor 1)O2 sensor failure
Harness failure
Connector pin(s) bent or tracking
between connections. ECM failure
*
*
*
*GO to Pinpoint Test A
*
DTC P0137 O2 sensor circuit low voltage (Bank 1
sensor 2)O2 sensor failure
Sensor ground fault
Harness failure
Connector pin(s) bent, loose or corroded
*
*
*
*GO to Pinpoint Test C
*
DTC P0138 O2 sensor circuit high voltage (Bank
1 sensor 2)O2 sensor failure to B+
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
*
*
*
*GO to Pinpoint Test C
*
Page 1534 of 2490

Pinpoint test A: P0131, P0132, P0135
between connections. ECM failure
*
DTC P0140 O2 sensor circuit no activity detected
(Bank 1 sensor 2)O2 sensor failure / out of spec
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. Low exhaust temperature
*
*
*
*
*GO to Pinpoint Test D
*
DTC P0420 Catalyst system efficiency below
threshold (bank 1)Downstream O2 sensor failure
Catalyst failure
Catalyst low temperature caused by
water splash
*
*
*GO to Pinpoint Test C
GO to Pinpoint Test D
*
*
DTC P0151 O2 sensor circuit low voltage (Bank 2
sensor 1)O2 sensor failure
Sensor ground fault
Harness failure
Connector pin(s) bent, loose or corroded
*
*
*
*GO to Pinpoint Test E
*
DTC P0152 O2 sensor circuit high voltage (Bank
2 sensor 1)O2 sensor failure to B+
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. O2 sensor failure
*
*
*
*
*GO to Pinpoint Test E
*
DTC P0153 O2 sensor circuit slow response
(Bank 2 sensor 1)O2 sensor heater failure / out of spec
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. Low exhaust temperature
O2 sensor failure
*
*
*
*
*
*GO to Pinpoint Test F
*
DTC P0155 O2 sensor heater circuit malfunction
(Bank 2 sensor 1)O2 sensor failure
Harness failure
Connector pin(s) bent or tracking
between connections. ECM failure
*
*
*
*GO to Pinpoint Test E
*
DTC P0157 O2 sensor circuit low voltage (Bank 2
sensor 2)O2 sensor failure
Sensor ground fault
Harness failure
Connector pin(s) bent, loose or corroded
*
*
*
*GO to Pinpoint Test G
*
DTC P0158 O2 sensor circuit high voltage (Bank
2 sensor 2)O2 sensor failure to B+
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. ECM failure
*
*
*
*
*GO to Pinpoint Test G
*
DTC P0160 O2 sensor circuit no activity detected
(Bank 2 sensor 2)O2 sensor failure / out of spec
Sensor ground fault
Harness failure
Connector pin(s) bent or tracking
between connections. Low exhaust temperature
*
*
*
*
*GO to Pinpoint Test H
*
DTC P0430 Catalyst system efficiency below
threshold (bank 2)Downstream O2 sensor failure
Catalyst failure
Catalyst low temperature caused by
water splash
*
*
*GO to Pinpoint Test G
GO to Pinpoint Test H
*
*
PINPOINT TEST A : P0131, P0132, P0135
TEST CONDITIONSDETAILS/RESULTS/ACTIONS
A1: RETRIEVE DTCS
• NOTE: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.
Page 1760 of 2490

Symp
tom #5
Sy
m
ptom #5
Low r
e
frigerant charge
*
Check f or 'hissi
ng' at expansion
valve; may be witnessed by low
HIGH side pressure. Recover / recharge
*
Moi
s
ture or air in the system
*
Chec k syst
em pressures
*
Heat er ci
rcuit air-lock
*
R e
fer section 303-03 for fill / bleed procedure
*
Suct ion
pipe touching bank 1 (A)
cylinder head (rubber isolator
missing)
*
Check the pi
pe cluster for correct fitti
ng
*
• NOTE: Electrical faults may be more rapidly traced using PDU
Sym
ptom
Possib
l
e Sources
Acti
o
n
Insuffi
ci
ent
heating
Coo l
ant flow valve stuck 'closed'
Coolant flow valve stuck 'open' allowing recirculation of
coolant at engine idle
*
*
Re
new v
alve
*
Motorized in-car aspirator sei zed
*R e
new aspirator
*
Coo l
air bypass damper stuck open
*
Re new,
check fault code #43
*
B l
ocked air inlet / pollen filter
*
Chec k / cl
ean / renew
*
B l
ower speed low
*
Check performance range
*
Low cool ant
level
*
Adjust as req u
ired (verify and correct
reason for loss)
*
Engine
t
hermostat faulty
*
Check engine r u
nning temperature
*
Heater water pump seized
*Chec k op
eration
*
Heater ma trix
blocked
*
Re new m
atrix
*
Heater circui t
air-lock
*
R e
fer section 303-03 for fill / bleed
procedure
*
Sym
p
tom #4
Sym
ptom #4
Sy
m
ptom
Possib
l
e Sources
Acti
o
n
No
i
sy
system
Loose or damaged compressor drive
belt
*Adjust or r
e
new
*
Loose compressor mountings
*Check f o
r damage, tighten to specification if OK
*
Compressor oil level l
ow
*
Look for evidence of l
eakag
e and rectify as required
*
Compressor internal dama ge
*Check f o
r debris, renew compressor and receiver drier
*
B l
ower motor noise
*
Re new m
otor (assuming no fan interference)
*
Excessive refrige rant charge
*Check f o
r vibration or 'thumping'
in high pressure line; may be
witnessed by high pressure on both HIGH and LOW sides.
Recover / recharge
*