CTS 2003-2005

3.8L V6 VIN 1 Auto 1

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3.8L V6 VIN 1 Auto

Trouble Code: P0101



MAF Sensor Signal Range/Performance

Possible Causes:



Base engine vacuum leak, PCV valve leaking or stuck open
 
Engine oil dipstick missing or not fully seated
 
MAF sensor signal or ground circuit fault or sensor has failed
 
PCM has failed
 

Trouble Code: P0102



MAF Sensor Circuit Low Frequency

Possible Causes:



MAF sensor element hot wire contaminated or the sensor failed
 
MAF sensor signal shorted to ground or ground circuit problem
 
MAF sensor wiring routed close to the ignition wires, generator, solenoids or electric motors
 
PCM has failed
 

Trouble Code: P0103



MAF Sensor Circuit High Frequency

Possible Causes:



MAF sensor power circuit has a high resistance condition
 
MAF sensor is contaminated, dirty or it has failed
 
MAF sensor wiring routed close to Generator or ignition wires
 
Water enters the air intake system reaches the MAF sensor, cools it, and causes it to indicate excessive airflow (check AIR system)
 
PCM has failed
 

Trouble Code: P0107



MAP Sensor Circuit Low Input

Possible Causes:



MAP sensor signal circuit shorted to sensor ground
 
MAP sensor power circuit open between the sensor and PCM
 
MAP sensor is damaged or has failed
 
PCM has failed
 

Trouble Code: P0108



MAP Sensor Circuit High Input

Possible Causes:



MAP sensor signal circuit is open or it is shorted to VREF
 
MAP sensor ground circuit open between sensor and the PCM
 
MAP sensor is damaged or has failed
 
PCM has failed
 

Trouble Code: P0112



IAT Sensor Circuit Low Input

Possible Causes:



IAT sensor signal circuit is shorted to sensor or chassis ground
 
IAT sensor is damaged or has failed (it may be shorted)
 
PCM has failed
 

Trouble Code: P0113



IAT Sensor Circuit High Input

Possible Causes:



IAT sensor signal circuit is open between the sensor and PCM
 
IAT sensor signal circuit is shorted to VREF or system power
 
IAT sensor is damaged or has failed (it may be open)
 
PCM has failed
 

Trouble Code: P0116



ECT Sensor Signal Range/Performance

Possible Causes:



ECT sensor circuit has an intermittent high resistance condition
 
ECT sensor circuit has an intermittent grounded condition
 
ECT sensor is out of calibration or "skewed"
 

Trouble Code: P0117



ECT Sensor Circuit Low Input

Possible Causes:



ECT sensor signal circuit shorted to sensor or chassis ground
 
ECT sensor is damaged or has failed (it may be shorted)
 
PCM has failed
 

Trouble Code: P0118



ECT Sensor Circuit High Input

Possible Causes:



ECT sensor signal circuit is open between the sensor and PCM
 
ECT sensor signal circuit is shorted to VREF or system power
 
ECT sensor is damaged or has failed (it may be open)
 
PCM has failed
 

Trouble Code: P0121



TP Sensor Signal Range/Performance

Possible Causes:



TP sensor signal circuit open or shorted to ground (intermittent)
 
TP sensor VREF circuit is open or shorted (intermittent fault)
 
TP sensor is damaged or it failed (may be cracked or sticking)
 
PCM has failed
 

Trouble Code: P0122



TP Sensor Circuit Low Input

Possible Causes:



TP sensor signal circuit is shorted to sensor ground
 
TP sensor signal circuit is open (except 1996-1998 models)
 
TP sensor VREF circuit is open between sensor and PCM
 
TP sensor is damaged or it failed (it may be shorted)
 
PCM is damaged or has failed
 

Trouble Code: P0123



TP Sensor Circuit High Input

Possible Causes:



TP sensor signal circuit is shorted to VREF or system power
 
TP sensor ground circuit is open between the sensor and PCM
 
TP sensor is damaged or it failed (it may be open)
 
PCM is damaged or has failed
 

Trouble Code: P0125



ECT Excessive Time To Enter Closed Loop

Possible Causes:



Check the operation of the thermostat (it may be stuck open)
 
Coolant level is too low, or the coolant mixture is incorrect
 
ECT sensor signal circuit has a high resistance condition
 
ECT sensor is damaged or it has failed
 

Trouble Code: P0128



ECT Sensor Below Thermostat Regulating Temperature

Possible Causes:



Check the operation of the thermostat (it may be stuck open)
 
Coolant level is too low, or the coolant mixture is incorrect
 
ECT sensor is damaged or it has failed
 

Trouble Code: P0131



HO2S-11 (Bank 1 Sensor 1) Circuit Low Input

Possible Causes:



Air leaks in the exhaust system, intake manifold, vacuum lines
 
Engine misfire condition present (look for P0300 series codes)
 
Fuel system too lean (possible low fuel pressure, water in fuel)
 
HO2S signal circuit is shorted to the sensor or chassis ground
 
HO2S is damaged (i.e., cracked) or air reference hole clogged
 
PCM has failed
 

Trouble Code: P0132



HO2S-11 (Bank 1 Sensor 1) Circuit High Input

Possible Causes:



Fuel system is too rich (fuel pressure too high, fuel pressure regulator leaking, or one or more fuel injectors sticking/leaking)
 
HO2S element is silicon, water or fuel contaminated
 
HO2S signal tracking (water intrusion) in the connector causing a short between the HO2S signal and heater power circuits
 
PCM has failed
 

Trouble Code: P0133



HO2S-11 (Bank 1 Sensor 1) Slow Response

Possible Causes:



Exhaust leak present in the exhaust manifold or exhaust pipes
 
Fuel system is too rich (fuel pressure too high, fuel pressure regulator leaking, or one or more fuel injectors sticking/leaking)
 
HO2S element is silicon, water or fuel contaminated or it failed
 
TP sensor element broken (can cause false acceleration event)
 
PCM has failed
 

Trouble Code: P0134



HO2S-11 (Bank 1 Sensor 1) Insufficient Activity

Possible Causes:



HO2S heater is damaged or has failed
 
HO2S signal or ground circuit has a high resistance condition
 
HO2S signal circuit is open or shorted to system power (B+)
 
HO2S has failed (i.e., it is silicon, water or fuel contaminated)
 
PCM has failed
 

Trouble Code: P0135



HO2S-11 (Bank 1 Sensor 1) Heater Circuit Malfunction

Possible Causes:



HO2S heater ground circuit is open or has high resistance
 
HO2S heater power circuit is open (test O2S fuse in fuse block)
 
HO2S heater element is damaged or has failed
 
PCM has failed
 

Trouble Code: P0137



HO2S-12 (Bank 1 Sensor 2) Circuit Low Input

Possible Causes:



Air leaks in the exhaust system, intake manifold, vacuum lines
 
Engine misfire condition present (look for P0300 series codes)
 
Fuel system too lean (possible low fuel pressure, water in fuel)
 
HO2S signal circuit is shorted to the sensor or chassis ground
 
HO2S is damaged (i.e., cracked) or air reference hole clogged
 
PCM has failed
 

Trouble Code: P0138



HO2S-12 (Bank 1 Sensor 2) Circuit High Input

Possible Causes:



Fuel system is too rich (fuel pressure too high, fuel pressure regulator leaking, or one or more fuel injectors sticking/leaking)
 
HO2S element is silicon, water or fuel contaminated
 
HO2S signal tracking (water intrusion) in the connector causing a short between the HO2S signal and heater power circuits
 
PCM has failed
 

Trouble Code: P0140



HO2S-12 (Bank 1 Sensor 2) Insufficient Activity

Possible Causes:



Exhaust leak present in the exhaust manifold or exhaust pipes
 
HO2S signal or ground circuit has a high resistance condition
 
HO2S element is silicon, water or fuel contaminated
 
PCM has failed
 

Trouble Code: P0141



HO2S-12 (Bank 1 Sensor 2) Heater Circuit Malfunction

Possible Causes:



HO2S heater ground circuit is open or has high resistance
 
HO2S heater power circuit is open (test O2 fuse in fuse block)
 
HO2S heater element is damaged or has failed
 
PCM has failed
 

Trouble Code: P0171



Fuel Trim System Lean (Bank 1)

Possible Causes:



Air leaks in intake manifold, exhaust pipes or exhaust manifold
 
Fuel control sensor is out of calibration (ECT, IAT or MAF)
 
Low fuel pressure (fuel filter clogged, pressure regulator failure)
 
One or more injectors restricted or pressure regulator has failed
 
HO2S element is contaminated, deteriorated or has failed
 
Vacuum hose is disconnected, broken, leaking or loose
 

Trouble Code: P0172



Fuel Trim System Rich (Bank 1)

Possible Causes:



Base engine "mechanical" fault affecting one or more cylinders
 
Excess fuel vapors in crankcase (the oil needs to be changed)
 
EVAP system component has failed or canister fuel saturated
 
Fuel control sensor is out of calibration (i.e., ECT, IAT or MAF)
 
Fuel delivery system supplying too much fuel during cruise or idle periods (e.g., faulty fuel pump, or faulty pressure regulator)
 
Fuel injector(s) is leaking or stuck partially open (one or more)
 
HO2S is contaminated, deteriorated or it has failed
 

Trouble Code: P0201



Fuel Injector 1 Control Circuit Malfunction

Possible Causes:



Injector 1 power circuit (B+) is open (check the power fuse)
 
Injector 1 control circuit is open between injector and PCM
 
Injector 1 control circuit is grounded between injector and PCM
 
Injector 1 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0202



Fuel Injector 2 Control Circuit Malfunction

Possible Causes:



Injector 2 power circuit (B+) is open (check the power fuse)
 
Injector 2 control circuit is open between injector and PCM
 
Injector 2 control circuit is grounded between injector and PCM
 
Injector 2 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0203



Fuel Injector 3 Control Circuit Malfunction

Possible Causes:



Injector 3 power circuit (B+) is open (check the power fuse)
 
Injector 3 control circuit is open between injector and PCM
 
Injector 3 control circuit is grounded between injector and PCM
 
Injector 3 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0204



Fuel Injector 4 Control Circuit Malfunction

Possible Causes:



Injector 4 power circuit (B+) is open (check the power fuse)
 
Injector 4 control circuit is open between injector and PCM
 
Injector 4 control circuit is grounded between injector and PCM
 
Injector 4 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0205



Fuel Injector 5 Control Circuit Malfunction

Possible Causes:



Injector 5 power circuit (B+) is open (check the power fuse)
 
Injector 5 control circuit is open between injector and PCM
 
Injector 5 control circuit is grounded between injector and PCM
 
Injector 5 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0206



Fuel Injector 6 Control Circuit Malfunction

Possible Causes:



Injector 6 power circuit (B+) is open (check the power fuse)
 
Injector 6 control circuit is open between injector and PCM
 
Injector 6 control circuit is grounded between injector and PCM
 
Injector 6 is damaged or it has failed
 
PCM is damaged
 

Trouble Code: P0218



Transmission Fluid Over-Temperature (4T60-E, 4T65-E)

Possible Causes:



ATF is low, contaminated, burnt or dirty
 
Engine cooling system has an airflow restriction
 
Transmission cooling system has an airflow restriction
 
Transmission cooler lines are bent, damaged or restricted
 
Transmission internal failure (i.e., low line pressure, TCC fault)
 

Trouble Code: P0230



Fuel Pump Control Circuit Malfunction

Possible Causes:



Fuel pump relay power circuit is open (test B+ from fuse box)
 
Fuel pump control circuit is open or shorted to ground
 
Fuel pump control circuit is shorted to system power
 
PCM has failed
 
TSB 00-06-04-023 contains a repair procedure for this code
 

Trouble Code: P0243



Supercharger Boost Solenoid Control Circuit Malfunction

Possible Causes:



Boost solenoid circuit is open between the solenoid and PCM
 
Boost solenoid circuit is shorted to ground
 
Boost solenoid power circuit is open to system power
 
Boost solenoid is damaged or has failed
 
PCM has failed
 

Trouble Code: P0300



Multiple Engine Misfire Detected

Possible Causes:



Base engine mechanical fault that affects one or more cylinders
 
Fuel metering fault (high fuel pressure or fuel contaminated)
 
EVAP system problem or the EVAP canister is fuel saturated
 
EGR valve is stuck open or the PCV system has a vacuum leak
 
Ignition system fault (a coil) that affects more than one cylinder
 
MAF sensor contamination (it can cause a very lean condition)
 
TSB 99-06-04-005B contains a repair procedure for this code
 
TSB 03-06-04-030 contains a repair procedure for this code
 

Trouble Code: P0301



Cylinder 1 Misfire Detected

Possible Causes:



Air leak in the intake manifold, or in the EGR or PCV system
 
Base engine mechanical fault that affects only Cylinder 1
 
Fuel delivery component fault that affects only Cylinder 1 (i.e., a contaminated, dirty or sticking fuel injector)
 
Ignition system problem (coil, plug) that affects only Cylinder 1
 

Trouble Code: P0302



Cylinder 2 Misfire Detected

Possible Causes:



Air leak in the intake manifold, or in the EGR or PCV system
 
Base engine mechanical fault that affects only Cylinder 2
 
Fuel delivery component fault that affects only Cylinder 2 (i.e., a contaminated, dirty or sticking fuel injector)
 
Ignition system problem (coil, plug) that affects only Cylinder 2
 

Trouble Code: P0303



Cylinder 3 Misfire Detected

Possible Causes:



Air leak in the intake manifold, or in the EGR or PCV system
 
Base engine mechanical fault that affects only Cylinder 3
 
Fuel delivery component fault that affects only Cylinder 3 (i.e., a contaminated, dirty or sticking fuel injector)
 
Ignition system problem (coil, plug) that affects only Cylinder 3
 

Trouble Code: P0304



Cylinder 4 Misfire Detected

Possible Causes:



Air leak in the intake manifold, or in the EGR or PCV system
 
Base engine mechanical fault that affects only Cylinder 4
 
Fuel delivery component fault that affects only Cylinder 4 (i.e., a contaminated, dirty or sticking fuel injector)
 
Ignition system problem (coil, plug) that affects only Cylinder 4
 

 
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