Engine Controls - 5.7l - Diagnosis (DTC p0172 - p0507) Cadillac CTS I

Circuit Description

The powertrain control module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop the PCM determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During Closed Loop, the oxygen sensor inputs are added and used by the PCM to calculate short and long term fuel trim fuel delivery adjustments. If the HO2S indicate a lean condition, the fuel trim values will be above 0 percent. If the HO2S indicate a rich condition, the fuel trim values will be below 0 percent. Short term fuel trim values change rapidly in response to the HO2S voltage signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. The fuel trim diagnostic will conduct a test to determine if a rich failure actually exists, or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition. If the PCM detects an excessively rich condition, DTC P0172 or P0175 sets.

Conditions for Running the DTC

1. DTCs P0101, P0103, P0108, P0135, P0137, P0141, P0200, P0300, P0420, P0430, P0442, P0443, P0446, P0449, P0506, or P0507 are not set.
2. The engine coolant temperature (ECT) is between 75-115° C (167-239° F).
3. The intake air temperature (IAT) is between -20 and +90° C (4-194° F).
4. The manifold absolute pressure (MAP) is between 26-90 kPa (3.8-13 psi).
5. The vehicle speed is less than 137 km/h (85 mph).
6. The engine speed is between 400-3,000 RPM.
7. The barometric pressure (BARO) is more than 74 kPa (10.7 psi).
8. The mass airflow (MAF) is between 5-90 g/s.
9. The fuel level is more than 10 percent.
10. The throttle position (TP) is less than 90 percent.

Conditions for Setting the DTC

1. The average long term fuel trim value is below -13 percent.
2. All of the above conditions are present for 40 seconds.

Action Taken When the DTC Sets

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

1. Fuel contamination, such as water or alcohol will effect fuel trim.
2. A malfunctioning mass air flow sensor can cause a rich condition and set this DTC. Refer to «DTC P0101»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-diagnosis-dtc-p0068-p0174) .
3. Use a scan tool in order to review Failure Records. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

Test Description

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

1. 7: An EVAP canister that is saturated will cause a rich condition.

DTC P0172 or P0175

The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver. The control module monitors the status of each driver. If the control module detects an incorrect voltage for the commanded state of the driver, DTC P0200 sets.

1. The engine speed is more than 400 RPM.
2. The ignition voltage is between 6-18 volts.

1. The powertrain control module (PCM) detects an incorrect voltage on a fuel injector control circuit.
2. The condition exists for 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Performing the Fuel Injector Coil Test may help to isolate an intermittent condition. Refer to «Fuel Injector Coil Test»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting) .
2. For an intermittent condition, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 5: This step verifies that the PCM is able to control the fuel injector.
2. 7: This step tests if a ground is constantly being applied to the fuel injector.

DTC P0200

The throttle position (TP) sensor is mounted on the throttle body assembly. The sensor is actually 2 individual TP sensors within 1 housing. Two separate signal, low reference and 5-volt reference circuits are used in order to connect the TP sensor assembly to the throttle actuator control (TAC) module. The 2 sensors have opposite functionality. The TP sensor 1 signal voltage is pulled up to the reference voltage as the throttle opens, from below 1 volt at closed throttle to above 3.5 volts at wide open throttle (WOT). The TP sensor 2 signal voltage is pulled down to the low reference from around 3.8 volts at closed throttle to below 1 volt at WOT. TP sensor 1 and accelerator pedal position (APP) sensor 1 share a 5-volt reference circuit that is connected within the TAC module. TP sensor 2 and APP sensor 2 share a 5-volt reference circuit that is connected within the TAC module. If an out of range condition is detected with the TP sensor 2, this DTC will set and the Reduced Engine Power message will be displayed.

1. DTCs P2108, or P1518 are not set.
2. The ignition switch in the crank position or the run position.
3. The ignition voltage is greater than 5.23 volts.

1. The TP sensor 2 voltage is less than 0.13 volts or greater than 4.87 volts.
2. All above conditions present for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the Capture Info.
3. If this DTC is determined to be intermittent, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 12: Using a test lamp reduces the amount of current fed into the signal circuit. The scan tool should display the maximum value for this parameter, 5-volts even though the actual voltage is higher.
2. 18: The TP 2 sensor and the APP 2 sensor share a common 5 volt reference. The 5-volt reference circuits are connected internally within the TAC module. Disconnecting the TAC module will isolate the 5-volt reference circuits.
3. 19: The TP sensor 2 and the APP sensor 2 share a common 5-volt reference. A short to voltage on the APP sensor 2 5-volt reference circuit will affect the TP sensor 2 5-volt reference circuit.
4. 36: When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This condition is due to the many redundant tests that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the Capture Info.

DTC P0220

When the ignition switch is turned ON, the control module enables the fuel pump relay, which supplies current to the fuel pump. The fuel pump remains enabled as long as the engine is cranking or running and the control module receives ignition reference pulses. If there are no ignition reference pulses, the control module shuts the fuel pump OFF approximately 2 seconds after the ignition was switched to the ON position or after the engine stops. The control module monitors the voltage on the fuel pump relay control circuit. If the control module detects an incorrect voltage on the fuel pump relay control circuit, DTC P0230 sets.

1. The engine speed is more than 400 RPM.
2. The ignition voltage is between 6-18 volts.

1. The Powertrain Control Module (PCM) detects that the commanded state of the driver and the actual state of the control circuit do not match.
2. The above conditions are present for a minimum of 2.5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 4: This step verifies that the PCM is providing voltage to the fuel pump relay.
2. 5: This step tests for an open in the ground circuit to the fuel pump relay.
3. 6: This step tests if the voltage is constantly being applied to the control circuit of the fuel pump relay.

DTC P0230

System Description

The powertrain control module (PCM) uses information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.

1. DTC P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0125, P0128, P0335, P0336, P0341, P0342, P0343, P0410, P0500, P0502, P0503, P1114, P1115, P1120, and P1220 are not set.
2. The engine speed is between 425-3,000 RPM.
3. The ignition voltage is between 10-18 volts.
4. The engine coolant temperature (ECT) is between -7 and +130° C (19-266° F).
5. The fuel level is more than 10 percent.
6. The throttle angle is steady within 1 percent.
7. The antilock brake system (ABS) and the traction control system are not active.
8. The transmission is not changing gears.
9. The A/C clutch is not changing states.
10. The PCM is not in fuel shut-off or decel fuel cut-off mode.
11. The PCM is not receiving a rough road signal.

The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Excessive vibration from sources other than the engine could cause DTC P0300 to set. The following are possible sources of vibration: Variable thickness brake rotors-Refer to «Symptoms - Hydraulic Brakes»(/cadillac/cts/i-2002-2007/remont/mechanical-hydraulic/#hydraulic-brake-system__symptoms-hydraulic-brakes) in Hydraulic Brakes. Drive shaft not balanced-Refer to «Vibration Analysis - Driveline»(/cadillac/cts/i-2002-2007/remont/oem-general-information/#vibration-symptoms-diagnosis-and-correction) in Vibration Diagnosis and Correction. Worn or damaged accessory drive belt-Refer to «Base Engine Misfire without Internal Engine Noises»(/cadillac/cts/i-2002-2007/remont/mechanical/#engine-mechanical-57l-ls6__base-engine-misfire-without-internal-engine) in Engine Mechanical.
2. There may be more or less cylinders actually misfiring than indicated by the scan tool.
3. Spray water on the secondary ignition components using a spray bottle. Look and listen for arcing or misfiring.
4. If there are multiple misfires on only one bank, inspect the fuel injector and ignition coil, power and ground circuits for that bank. Refer to «Engine Controls Schematics»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-introduction) .

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

1. 2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.
2. 3: DTC P0135 or P0155 can be set because of a misfire.

DTC P0300

The Crankshaft Position (CKP) System Variation Learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the crankshaft position sensor. The calculated error allows the powertrain control module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.

The PCM stores the crankshaft position system variation values after a learn procedure has been performed. If the actual crankshaft position variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set. If the PCM detects the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.

1. DTCs P0335, P0336, P0341, P0342, P0343 are not set.
2. The engine coolant temperature is more than 70° C (158° F).

The CKP system variation values are not stored in the PCM memory.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0315

The knock sensors (KS) produce an AC signal under all engine operating conditions. The powertrain control module (PCM) calculates the average voltage range of each KS signal. If the KS system is operating normally, the PCM should monitor the KS voltage varying above and below a calculated average voltage. This DTC will set if the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system.

1. Engine run time is more than 10 seconds.
2. Ignition voltage is more than 10 volts.

1. A malfunction with the KS system within the PCM are faulty.
2. All of the above conditions are present for 12 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0325

The knock sensors (KS) produce an AC signal under all engine operating conditions. The powertrain control module (PCM) calculates the average voltage range of each KS signal. If the KS system is operating normally, the PCM should monitor the KS voltage varying above and below calculated average voltage. If the PCM detects a KS-1 signal or a KS-2 signal voltage within the calculated average range, a DTC will be set. DTC P0327 refers to the front knock sensor. DTC P0332 refers to the rear knock sensor.

1. DTCs P0117, P0118, P0121, P0122, P0123, P0125, P1114, P1115, P1121 or P1122 are not set.
2. The minimum noise level must be learned. The minimum noise level is learned when the following conditions are met: The ECT must be greater than 60° C (140° F). The engine RPM is between 475-975 for 10 seconds.
3. Engine speed is between 1500 RPM and 3,000 RPM.
4. Map is less than 49 kPa.
5. Engine coolant temperature (ECT) is more than 60° C (140° F).
6. Throttle angle is more than 0 percent.
7. Engine run time is more than 10 seconds.
8. Ignition voltage is more than 10 volts.

The PCM determines that this signal is less than the expected amount for more than 9 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Check the knock sensor for proper installation. A knock sensor that is loose or over torqued may cause the DTC to set.
2. If DTCs P0327 and P0332 are set at the same time, inspect for poor connections at the KS harness jumper, located at the left rear side of the intake manifold.
3. For an intermittent, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 2: This verifies the malfunction is present.
2. 3: This test will isolate the knock sensor from the rest of the circuit.
3. 4: Tapping on the engine block will simulate an engine knock.

DTC P0327 or P0332

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor is connected directly to the powertrain control module (PCM) and consists of the following circuits

1. The 12-volt reference circuit
2. The low reference circuit
3. The CKP sensor signal circuit

If the PCM detects no signal from the CKP sensor for less than 4 seconds.

1. DTCs P0101, P0102, P0103, P0341, P0342, or P0343 are not set.
2. The camshaft position (CMP) sensor is in transition.
3. The mass airflow (MAF) is more than 3 grams per second.
4. The ignition switch is in the crank mode.

The PCM does not receive signals from the CKP sensor for less than 4 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 6: This step simulates a CKP sensor signal to the PCM. If the PCM receives the signal, the fuel pump will operate for 2 seconds. If the fuel pump operates, the condition involves terminal contact at one of the following components: The CKP sensor The CKP sensor reluctor wheel

DTC P0335

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor is connected directly to the powertrain control module (PCM) and consists of the following circuits

1. The 12-volt reference circuit
2. The low reference circuit
3. The CKP sensor signal circuit

If the PCM detects that the CKP sensor is inconsistent for less than 2 seconds.

The engine is cranking or running.

The PCM determines that the CKP sensor signal is for less than 2 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 3: This step tests for electromagnetic interference (EMI) on the CKP sensor circuits.
2. 6: Vertical lines across the face of the sensor may indicate foreign material passing between the CKP sensor and the reluctor wheel. Lines which are not vertical across the face of the sensor may indicate a crack in the CKP sensor. Either of these conditions will cause this DTC to set.
3. 7: Damage to the reluctor wheel can affect the CKP sensor output.

DTC P0336

The camshaft position (CMP) sensor works in conjunction with a 1 X reluctor wheel on the camshaft. The powertrain control module (PCM) provides a 12 volt reference to the CMP sensor as well as a low reference and a signal circuit.

As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this 1 X signal in combination with the crankshaft position (CKP) sensor signal in order to determine the CKP and stroke.

The CMP sensor 1 X signal is used by the PCM to determine if the cylinder at top dead center (TDC) is on the firing stroke or the exhaust stroke. The PCM can determine TDC for all cylinders by using the CKP sensor signal alone. Observe that as long as the PCM receives the CKP sensor signal, the engine will start without a CMP signal. A slightly longer cranking time may be a symptom of this condition. The system attempts synchronization and looks for an increase in engine speed indicating that the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes that the PCM incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. If the PCM detects that a CMP to CKP mis-match has occurred DTC P0341 sets.

The engine is running and the engine speed is less than 4,000 RPM.

The PCM detects that a CMP to CKP mis-match has occurred.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

The following conditions may cause this DTC to set

1. Camshaft reluctor ring damage
2. The sensor coming in contact with the reluctor ring
3. Foreign material passing between the sensor and the reluctor ring
4. Excessive camshaft end-play
5. Wiring routed too close to secondary ignition components

If you suspect the condition is intermittent, refer to Intermittent Conditions .

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

1. 3: This step inspects for electromagnetic interference (EMI) on the CMP sensor circuits.
2. 6: Damage to the face of the sensor could indicate foreign material passing between the CMP sensor and the reluctor wheel. This condition would cause this DTC to set. Damage to the reluctor wheel would affect the CMP sensor output.

DTC P0341

The camshaft position (CMP) sensor works in conjunction with a 1 X reluctor wheel on the camshaft. The powertrain control module (PCM) provides a 12-volt reference to the CMP sensor as well as a low reference and a signal circuit.

As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this 1X signal in combination with the crankshaft position (CKP) sensor signal in order to determine the CKP and stroke.

The CMP sensor 1X signal is used by the PCM to determine if the cylinder at top dead center (TDC) is on the firing stroke or the exhaust stroke. The PCM can determine TDC for all cylinders by using the CKP sensor signal alone. Observe that as long as the PCM receives the CKP sensor signal, the engine will start without a CMP signal. A slightly longer cranking time may be a symptom of this condition. The system attempts synchronization and looks for an increase in engine speed indicating that the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes that the PCM incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. If the PCM detects that the CMP signal is constantly low, DTC P0342 sets.

1. The engine is running.
2. The engine speed is less than 4,000 RPM.

The PCM detects that the CMP sensor signal is low for 1.5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. The following conditions may cause this DTC to set: Camshaft reluctor ring damage The sensor coming in contact with the reluctor ring Foreign material passing between the sensor and the reluctor ring Excessive camshaft end-play Wiring routed too close to secondary ignition components
2. If the condition is intermittent, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 4: This step tests the CMP sensor and circuits from the CMP sensor to the PCM. If there is not duty cycle displayed or if the duty cycle is not within range there is a problem with the sensor or the circuits.

DTC P0342

The camshaft position (CMP) sensor works in conjunction with a 1X reluctor wheel on the camshaft. The powertrain control module (PCM) provides a 12-volt reference to the CMP sensor as well as a low reference and a signal circuit.

As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The sensors internal circuitry detects this and produces a signal which the PCM reads.

The CMP sensor 1X signal is used by the PCM to determine if the cylinder at top dead center (TDC) is on the firing stroke or the exhaust stroke. The PCM can determine TDC for all cylinders by using the CKP sensor signal alone. The engine will start without a CMP signal as long as the PCM receives the CKP sensor signal. A slightly longer cranking time may be a symptom of this condition. The system attempts synchronization and looks for an increase in engine speed indicating that the engine started. If the PCM does not detect an increase in engine speed, the PCM assumes that the PCM incorrectly synchronized to the exhaust stroke and re-syncs to the opposite cam position. If the PCM detects that the CMP signal is constantly high, DTC P0343 sets.

1. The engine is running.
2. The engine speed is less than 4,000 RPM.

The PCM detects that the CMP sensor signal is high for 1.5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. The following conditions may cause this DTC to set: Camshaft reluctor ring damage The sensor coming in contact with the reluctor ring Foreign material passing between the sensor and the reluctor ring Excessive camshaft end-play Wiring routed too close to secondary ignition components
2. If the condition is intermittent, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 4: This step tests the CMP sensor and circuits from the CMP sensor to the PCM. If there is not duty cycle displayed or if the duty cycle is not within range there is a problem with the sensor or the circuits.

DTC P0343

The ignition system on this engine uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition system operation. The PCM controls each coil using one of eight ignition control (IC) circuits. The PCM commands the IC circuit low when a spark event is requested. This causes the IC module to energize the ignition coil to create a spark at the spark plug. Each ignition coil has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. An ignition control (IC) circuit
4. A low reference circuit

Sequencing and timing are PCM controlled. If the PCM detects that the IC circuit is out of range, DTC P0351-P0358 sets.

The engine is operating.

The PCM detects the IC circuit is grounded, open, or shorted to voltage for less than 1 second.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 3: This step verifies the integrity of the IC circuit and the PCM output.
2. 4: This step tests for a short to ground on the IC circuit.

DTC P0351-P0358

The three-way catalytic converter (TWC) reduces emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalyst within the converter promotes a chemical reaction, which oxidizes the HC and CO that are present in the exhaust gas. This process converts these chemicals into water vapor and carbon dioxide (CO2), and will reduce the NOx, by converting them into nitrogen. The catalytic converter also stores oxygen. The powertrain control module (PCM) monitors this process using heated oxygen sensor (HO2S) bank 1 sensor 2 and HO2S bank 2 sensor 2, located in the exhaust stream after the 3-way catalytic converter (TWC). These sensors are referred to as the catalyst monitor sensors. The catalyst monitor sensors produce an output signal that the PCM uses to indicate the oxygen storage capacity of the catalyst. This determines the catalyst's ability to effectively convert the exhaust emissions.

If the catalyst is functioning correctly, the HO2S bank 1 sensor 2 and the HO2S bank 2 sensor 2 signals will be far less active than the signals that are produced by the HO2S bank 1 sensor 1 and the HO2S bank 2 sensor 1. This indicates that the TWC oxygen storage capacity is at an acceptable threshold. When the response time of the catalyst monitor sensors are close to that of the fuel control sensors, the ability of the catalyst to store oxygen may be below an acceptable threshold.

The PCM performs this diagnostic test at idle. When the conditions for running this DTC are met, the following occurs

1. The air-to-fuel ratio transitions from lean to rich.
2. The air-to-fuel ratio transitions a second time rich to lean, opposite the first air-to-fuel ratio transition.
3. The PCM captures the response time of the front and the rear HO2S when the air-to-fuel ratio transitions occur. The HO2S response time changes from less than 350 mV to more than 600 mV, and from more than 600 mV to less than 350 mV.
4. The PCM measures the time necessary for the rear HO2S voltage to cross a reference lean-to-rich threshold, and the time necessary for the front HO2S voltage to cross the same lean-to-rich threshold. The difference between the front HO2S time and the rear HO2S time indicates the oxygen storage capacity of the catalyst. If the PCM detects that this time difference is less than a predetermined value, DTC P0420 for bank 1 or DTC P0430 for bank 2 sets.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0174, P0175, P0200, P0220, P0300, P0325, P0327, P0336, P0341, P0342, P0343, P0351-P0358, P0442, P0443, P0446, P0449, P0455, P0491, P0492, P0496, P0502, P0503, P0506, P0507, P1133, P1134, P1153, P1154, P1516, P1518, P2108, P2121, P2125, P2126, P2130, P2131, P2135 are not set.
2. The engine has been running for more than 10 minutes.
3. The intake air temperature (IAT) is between -7 and +85° C (+20 and +185° F).
4. The barometric pressure (BARO) is more than 74 kPa (10.7 psi).
5. The engine coolant temperature (ECT) is between 70-120° C (158-248° F).
6. Since the end of the last idle period, the engine speed has been more than 900 RPM for 42 seconds.
7. The Closed Loop fuel control is enabled.
8. The engine must be at a stable idle speed, within 200 RPM of desired idle.
9. The battery voltage is more than 10.7 volts.

The PCM determines that the oxygen storage capability of the TWC has degraded to less than a calibrated threshold.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. These conditions may cause a catalytic converter to degrade. Inspect for the following conditions: An engine misfire High engine oil or high coolant consumption Retarded spark timing A weak or poor spark A lean fuel mixture A rich fuel mixture A damaged oxygen sensor or wiring harness
2. If an intermittent condition cannot be duplicated, the information included in Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC was set.
3. The catalyst may have been temporarily contaminated with a chemical from a fuel additive, fuel contamination or any of the above conditions.
4. If the condition is determined to be intermittent, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 5: This step indicates that a catalytic converter which has been discolored may be due to an engine running rich, lean or had a previous misfire. Verifying the fuel trim percentages may be of assistance in determining if such a condition exists.
2. 6: This step inspects for conditions that can cause the TWC efficiency to appear degraded.

DTC P0420 or P0430

This diagnostic tests the Evaporative Emission (EVAP) System for a small leak when the key is turned OFF and the correct conditions are met.

Heat is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, a change in the fuel tank vapor temperature occurs, which results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 mm (0.020 inches) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.

If the control module detects a pressure change less than a calibrated amount, DTC P0442 sets.

1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0335, P0336, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0500, P0502, P0503, P1683 are not set.
2. The diagnostic runs once with a 10 hour minimum between tests after a fail.
3. DTC P0455 must run and pass.
4. The start up intake air temperature (IAT) is between 4-30° C (39-86° F).
5. The start up engine coolant temperature (ECT) is less than 30° C (86° F).
6. The start up IAT and ECT are within 8° C (15° F).
7. The barometric pressure (BARO) is more than 74 kPa.
8. The ambient air temperature is between 2-32° C (36-90° F).
9. The engine run time minimum is 10 minutes.
10. The odometer displays more than 10 miles.
11. The vehicle has traveled more than 3 miles this trip.
12. The ECT is more than 70° C (158° F).
13. The fuel level is between 15-85 percent.
14. The ignition is OFF.

The control module detects a pressure change that is less than a calibrated amount.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
2. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
3. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 3: Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
2. 5: This step verifies that repairs are complete and that no other condition is present.

DTC P0442

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.

1. The engine speed is more than 400 RPM.
2. The system voltage is between 6-18 volts.

1. The control module detects that the commanded state of the driver and the actual state of the control circuit do not match.
2. The above conditions are present for a minimum of 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 2: This step tests if the concern is active. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A clicking should be heard or felt when the EVAP canister purge solenoid valve is commanded to 50 percent and should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the EVAP canister purge solenoid valve cycles should increase as the commanded state is increased and decrease as the commanded state is decreased. Repeat the commands as necessary.
2. 5: This step tests if a ground is constantly being applied to the EVAP canister purge solenoid valve.
3. 6: This step verifies that the control module is providing ground to the EVAP canister purge solenoid valve.

DTC P0443

This DTC tests the Evaporative Emission (EVAP) System for a restricted or blocked EVAP canister vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

DTC P0446

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0442, P0443, P0449, P0452, P0453, P0455, P0502, P0503, P1112, P1114, P1115, P1120, P1133, P1134, P1153, P1154, P1220, P1221 are not set.
2. The ignition voltage is between 10-18 volts.
3. The barometric pressure (BARO) is more than 75 kPa.
4. The fuel level is between 15-85 percent.
5. The engine coolant temperature (ECT) is between 4-30° C (39-86° F).
6. The intake air temperature (IAT) is between 4-30° C (39-86° F).
7. The start up ECT and IAT are within 9° C (16° F) of each other.

1. The FTP sensor is less than -10 inches H2O.
2. The condition is present for more than 30 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the Vent System will also cause a poor fuel fill problem.
2. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions)

DTC P0446

An ignition voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.

DTC P0449

1. The engine speed is more than 400 RPM.
2. The system voltage is between 6-18 volts.

1. The control module detects that the commanded state of the driver and the actual state of the control circuit do not match.
2. The above conditions are present for a minimum of 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 2: A click should be heard or felt when the EVAP canister vent solenoid valve operates. Be sure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
2. 5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
3. 6: This step tests if the EVAP canister vent solenoid valve control circuit is grounded.

DTC P0449

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 goes below a calibrated value, this DTC sets.

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

DTC P0452

The ignition is ON.

1. The fuel tank pressure (FTP) sensor voltage is less than 0.1 volts
2. All conditions present for more than 5 seconds

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 5: Tests for the proper operation of the circuit in the high voltage range.

DTC P0452

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.

DTC P0453

The ignition is ON.

1. The fuel tank pressure (FTP) sensor voltage is more than 4.9 volts.
2. All conditions present for more than 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 2: If DTC P1639 is set, the 5-volt reference circuit may be shorted to a voltage.

DTC P0453

The control module tests the Evaporative Emission (EVAP) System for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.

DTC P0455

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0442, P0443, P0449, P0452, P0453, P1112, P1114, P1115, P1120, P1133, P1134, P1153, P1154, P1220, P1221 are not set.
2. The engine is running.
3. The ignition voltage is between 10-18 volts.
4. The barometric pressure (BARO) is more than 75 kPa.
5. The fuel level is between 15-85 percent.
6. The engine coolant temperature (ECT) is between 4-30° C (39-86° F).
7. The intake air temperature (IAT) is between 4-30° C (39-86° F).
8. The start-up ECT and IAT are within 9° C (16° F) of each other.
9. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP System. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
2. A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
3. To improve the visibility of the smoke exiting the EVAP System, observe the suspected leak area from different angles with the J 41413-SPT .
4. 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.
5. A condition may exist where a leak in the EVAP System only exists under a vacuum condition. By using the scan tool PURGE/SEAL function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay, this type of leak may be detected.
6. For intermittent conditions, refer to «Intermittent Conditions»(/cadillac/cts/i-2002-2007/remont/testing-diagnostics/#engine-controls-57l-troubleshooting__intermittent-conditions) .

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

1. 6: This step verifies proper operation of the FTP sensor.
2. 7: A normal operating FTP sensor should increase above 5 inches of H2O and stop between 6 inches of H2O and 7 inches of H2O.

DTC P0455

This DTC tests for undesired intake manifold vacuum flow to the Evaporative Emission (EVAP) System. The control module seals the EVAP System by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP System. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

DTC P0496

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0442, P0443, P0449, P0452, P0453, P0455, P1112, P1114, P1115, P1120, P1133, P1134, P1153, P1154, P1220, P1221 are not set.
2. The ignition voltage is between 10-18 volts.
3. The barometric pressure (BARO) is more than 75 kPa.
4. The fuel level is between 15-85 percent.
5. The engine coolant temperature (ECT) is between 4-30° C (39-86° F).
6. The intake air temperature (IAT) is between 4-30° C (39-86° F).
7. The start up ECT and IAT are within 9° C (16° F) of each other.
8. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

The control module detects vacuum during a non-purge condition.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0496

The throttle actuator control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle plate. In order to decrease idle speed the TAC system closes the throttle plate, reducing air flow into the engine. In order to increase idle speed the TAC system opens the throttle plate allowing more air flow into the engine. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this code sets.

1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0171, P0172, P0200, P0300, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1120, P1220, P1221, P1514, P1515, P1516, P1635, or P1639 are not set.
2. The engine is operating for at least 2 seconds.
3. The engine coolant temperature (ECT) is more than -40° C (-40° F).
4. The intake air temperature (IAT) is more than -40° C (-40° F).
5. The barometric pressure (BARO) is more than 65 kPa.
6. The system voltage is between 9-18 volts.
7. The vehicle speed is less than 4.8 km/h (3 mph).

1. The actual idle speed is approximately 150 RPM lower than or 100 RPM greater than the desired idle speed.
2. All above conditions present for 15 seconds.

1. The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
2. The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

1. The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using a scan tool.

If the condition is intermittent, refer to Intermittent Conditions .

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

1. 2: This test determines whether the engine can achieve the commanded RPM. If the engine does not reach the commanded RPMs, the test determines whether the RPM is too high or too low.

DTC P0506

The throttle actuator control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle plate. In order to decrease idle speed the TAC system closes the throttle plate, reducing air flow into the engine. In order to increase idle speed the TAC system opens the throttle plate allowing more air flow into the engine. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this code sets.

1. DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0125, P0171, P0172, P0200, P0300, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1120, P1220, P1221, P1514, P1515, P1516, P1635, or P1639 are not set.
2. The engine is operating for at least 2 seconds.
3. The engine coolant temperature (ECT) is more than -40° C (-40° F).
4. The intake air temperature (IAT) is more than -40° C (-40° F).
5. The barometric pressure (BARO) is more than 65 kPa.
6. The system voltage is between 9-18 volts.
7. The vehicle speed is less than 4.8 km/h (3 mph).

1. The actual idle speed is approximately 150 RPM lower than or 100 RPM greater than the desired idle speed.
2. All above conditions present for 15 seconds.

1. The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
2. The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

1. The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using a scan tool.

If the condition is intermittent, refer to Intermittent Conditions .

The number below refers to the step number in the diagnostic table.

1. 2: This test determines whether the engine can achieve the commanded RPM. If the engine does not reach the commanded RPM, the test determines whether the RPM is too high or too low.

DTC P0507

See also:
• DTC P0101
• Intermittent Conditions
• Diagnostic System Check - Engine Controls
• Diagnostic Trouble Code (DTC) List
• Evaporative Emissions (EVAP) Hose Routing Diagram
• Circuit Testing
• Wiring Repairs
• Fuel System Diagnosis
• Symptoms - Engine Mechanical
• Engine Controls Connector End Views
• Powertrain Control Module (PCM) Connector End Views
• Testing for Intermittent Conditions and Poor Connections
• Repairing Connector Terminals
• Probing Electrical Connectors
• Connector Repairs
• Symptoms - Hydraulic Brakes
• Vibration Analysis - Driveline
• Base Engine Misfire without Internal Engine Noises
• CKP System Variation Learn Procedure
• Restricted Exhaust
• Spark Plug Wire Inspection
• Spark Plug Inspection
• Measuring Frequency
• Testing for Continuity
• Testing for Short to Ground
• Lifting and Jacking the Vehicle
• Crankshaft and Bearings Removal
• Camshaft and Bearings Cleaning and Inspection
• Using Connector Test Adapters
• Exhaust Leakage
• Catalytic Converter Replacement - Left (LA3, LY9)
• Catalytic Converter Replacement - Left (LY7)
• Catalytic Converter Replacement - Left (LS6)
• Catalytic Converter Replacement - Right (LA3, LY9)
• Catalytic Converter Replacement - Right (LY7)
• Catalytic Converter Replacement - Right (LS6)
• Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement
• DTC P0420 or P0430