2003 Chevy Cavalier Error Codes

[dunkelight]

This is my first post so I apologize if i do something wrong. My check engine light has been on so i finally decided to check it again. A while ago I checked it and it complained of IAT temp sensor, so I went to the dealer, got a new one, and replaced it. I had the codes reset and the same code came back. I decided to not worry about it becuase I hadn't seen any difference in the mileage.

A few months later the mileage has started to degrade, i had the codes checked and now it comes up with two:

PO 113 - IAT Sensor 1 Circuit High Input

PO 453 - Evap. Emission Control System Pressure Sensor High

I've noticed about a 1/4 degredation in mileage.

Any help is much appreciated.

[Classicrocjunkie]

first one could be a faulty sensor.

last i hate evap codes and i don't have my GM dealer service manual handy either to double check those for you. I'm on spring break vacation. If you still have this issue when i get back, i'll check what it says out for you.

[Headnsouth]

DTC P0113
Circuit Description
The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.

Conditions for Running the DTC
• DTCs P0117, P0118, P0125, P0502, P0503 are not set.

• The engine run time is more than 5 minutes.

• The vehicle speed sensor indicates that vehicle speed is less than 24 km/h (15 mph).

Conditions for Setting the DTC
The PCM detects that the IAT sensor parameter is less than -39°C (-38°F) for more than 6 seconds.

Action Taken When the DTC Sets
• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

• Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
• When the vehicle is at ambient temperature, the IAT sensor and ECT sensor temperatures should be relatively close to each other. Refer to Temperature Versus Resistance .

• If an intermittent condition is suspected, refer to Intermittent Conditions .

Test Description
The number below refers to the step number on the diagnostic table.

This step tests for the proper operation of the circuit in the low voltage range.

Step
Action
Values
Yes
No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views

1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

2
Observe the intake air temperature (IAT) sensor parameter with a scan tool.

Is the IAT sensor parameter less than the specified value?
-39°C (-38°F)
Go to Step 4
Go to Step 3

3
Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 4
Go to Diagnostic Aids

4
Disconnect the IAT sensor.
Connect a DMM between the signal circuit of the IAT sensor and a good ground. Refer to Circuit Testing in Wiring Systems.
Is the voltage more than the specified value?
5.2 V
Go to Step 5
Go to Step 6

5
Important: The sensor may be damaged if the circuit is shorted to a voltage source.

Test the signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 12

6
Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the low reference circuit of the IAT sensor. Refer to Using Fused Jumper Wires in Wiring Systems.
Observe the IAT sensor parameter with a scan tool.
Is the IAT sensor parameter more than the specified value?
128°C (262°F)
Go to Step 10
Go to Step 7

7
Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and a good ground. Refer to Using Fused Jumper Wires in Wiring Systems.
Observe the IAT sensor parameter with a scan tool.
Is the IAT sensor parameter more than the specified value?
128°C (262°F)
Go to Step 9
Go to Step 8

8
Test the signal circuit of the IAT sensor for an open circuit or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 12

9
Test the IAT sensor low reference circuit for high resistance or for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 12

10
Test the IAT signal circuit for a short to any 5-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 11

11
Important: The sensor may be damaged if the circuit is shorted to a voltage source.

Test for an intermittent and for a poor connection at the IAT sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 13

12
Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 15
Go to Step 14

13
Replace the IAT sensor. Refer to Intake Air Temperature Sensor Replacement .

Did you complete the replacement?
--
Go to Step 15
--

14
Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?
--
Go to Step 15
--

15
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 2
Go to Step 16

16
Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK

DTC P0453
Circuit Description
The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage increases above a calibrated value, this DTC sets.

The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.

FTP Sensor Signal Voltage
Fuel Tank Pressure

High, Approximately 1.5 Volts or More
Negative Pressure/Vacuum

Low, Approximately 1.5 Volts or Less
Positive Pressure


Conditions for Running the DTC
The key is ON.

Conditions for Setting the DTC
• The fuel tank pressure (FTP) sensor voltage is more than 4.9 volts.

• All conditions are present for more than 5 seconds.

Action Taken When the DTC Sets
• The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the DTC
• A current DTC Last Test Failed clears when the diagnostic runs and passes.

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

• Clear the DTC with a scan tool.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step determines if the condition is present.

This step tests the signal circuit of the FTP sensor.

This step tests the ground circuit of the FTP sensor.

This step tests the 5-volt reference circuit of the FTP sensor.

Step
Action
Values
Yes
No

Schematic Reference: Engine Controls Schematics

Connect End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

2
Turn OFF the ignition.
Remove the fuel cap.
Turn ON the ignition, with the engine OFF.
Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
Is the Fuel Tank Pressure Sensor parameter more than the specified value?
4.3 V
Go to Step 4
Go to Step 3

3
Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Turn ON the ignition, with the engine OFF.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 4
Go to Intermittent Conditions

4
Install the fuel cap.
Disconnect the FTP sensor.
Observe the Fuel Tank Pressure Sensor parameter with a scan tool.
Is the Fuel Tank Pressure Sensor parameter more than the specified value?
0.2 V
Go to Step 7
Go to Step 5

5
Probe the ground circuit of the FTP sensor with a test lamp that is connected to battery voltage. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?
--
Go to Step 6
Go to Step 8

6
Measure the voltage of the FTP 5-volt reference circuit with a DMM. Refer to Circuit Testing in Wiring Systems.

Does the 5-volt reference circuit measure within the specified value?
4.8-5.2 V
Go to Step 10
Go to Step 11

7
Test the FTP signal circuit for a short to voltage or for a short to a 5-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 14
Go to Step 13

8
Test the FTP ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 14
Go to Step 9

9
Test for an intermittent and for a poor connection at the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 14
Go to Step 13

10
Test for an intermittent and for a poor connection at the FTP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 14
Go to Step 12

11
Repair the short to voltage in the FTP 5-volt reference circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?
--
Go to Step 14
--

12
Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?
--
Go to Step 14
--

13
Replace the control module. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?
--
Go to Step 14
--

14
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 2
Go to Step 15

15
Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List