Engine Controls and Fuel - 3.0l or 3.6l - DTC p0117 - DTC P21D/p2155 Cadillac CTS II

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Engine idling for 1 min. Observe the DTC information with a scan tool. DTCs P0117 and P0118 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Ignition Off all vehicle systems Off, this may take up to 2 minutes.Test for less than 5 ohms between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition ON, verify that the scan tool ECT sensor parameter is at -40°C (-40°F). If greater than the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K20 ECM.
Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the ECT sensor parameter is greater than 142°C (288°F). If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
If all circuits test normal, test or replace the B34 ECT sensor.

Component Testing

Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature (ECT) sensor.
Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5 % of the specification. If not within the specified range, replace the B34 ECT sensor.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
ECT Sensor Signal	P0117	P0116, P0118, P0119	P0118, P0119	P0116*
Low Reference		P0116, P0118, P0119	P0118, P0119	P0116*
* Internal ECM or sensor damage may occur if the circuit is shorted to B+

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: -39 to +142°C (-38 to +288°F) Varies with coolant temperature.
ECT Sensor Signal	143°C (289°F)	40°C (-40°F)	40°C (-40°F)*
Low Reference		40°C (-40°F)	40°C (-40°F)*
* Internal ECM or ECT sensor damage may occur if the circuit is shorted to B+

ECT Sensor

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the ECT sensor. If the ECM detects excessive noise or rapid fluctuations in the ECT signal, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

ECT	ECT Resistance	ECT Signal Voltage
Cold	High	High
Warm	Low	Low

Conditions for Running the DTC

DTC P0117 or P0118 is not set.
The ignition is ON or the engine is operating.
DTC P0119 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the ECT changed ±5°C (±9°F) greater than the expected value during a calibrated amount of time.
The condition exists for approximately 1 minute.

DTC P0119 is a Type B DTC.

Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a DTC or a driveability condition. Refer to «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__temperature-versus-resistance-engine-coolant) .
If the vehicle has sat overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
After starting a cold engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
High resistance on either the ECT sensor signal circuit or the ECT sensor low reference circuit could set a DTC.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Observe the scan tool engine coolant temperature (ECT) sensor parameter, while moving the ECT sensor connector and the K20 ECM connector. The ECT sensor parameter should not fluctuate while moving the related harnesses and connectors. Repair the suspected harness or connection if the ECT parameter fluctuates greater than 3°C (5°F) while moving the related harnesses and connectors.
Inspect the engine coolant level. Verify that the cooling system is operating correctly. If you suspect a condition with engine cooling system, refer to «Loss of Coolant»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Ignition OFF, remove the fuse that supplies B+ to circuit terminal 56 X2 of the K20 ECM.
Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance, or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to circuit terminal 56 X2 of the K20 ECM.
Ignition ON, verify that the scan tool ECT sensor parameter is at -40°C (-40°F). If warmer than the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 ECM.
Ignition ON, install a 3A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the ECT sensor parameter is greater than 142°C (288°F). If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
If all circuits test normal, test or replace the B34 ECT sensor.

Ignition OFF, disconnect the harness connector at the B34 engine coolant temperature (ECT) sensor.
Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5 percent of the specification. If not within the specified range, replace the B34 ECT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Engine Coolant Temperature Sensor Replacement (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
5-Volt Reference	P06A3		P0122, P0222	P0223, P06A3, P2135	P0121
TP Sensor 1 Signal	P0122	P2119, P2135, P2176	P0122	P0123, P2135	P0121, P2135
TP Sensor 2 Signal	P0222	P2135	P0223	P0223, P2135	P0121, P2135
Low Reference			P0122, P0223

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: The engine is idling. Parameter Normal Range: TP Sensor 1 3.00-4.0 V
5-Volt Reference	0.00 V	0.00 V	5.00 V
TP Sensor 1 Signal	0.00 V	0.00 V	5.00 V
Low Reference		4.98 V

TP Sensor 1

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: The engine is idling. Parameter Normal Range: TP Sensor 2 1.4-2.4 V
5-Volt Reference	0.02 V	0.00 V	5.00 V
TP Sensor 2 Signal	0.00 V	5.00 V	5.00 V
Low Reference		5.00 V

TP Sensor 2

Circuit/System Description

The throttle body assembly contains 2 throttle position (TP) sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the TP sensors with a common 5-volt reference circuit, a common low reference circuit, and 2 independent signal circuits.

The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases and TP sensor 2 signal voltage increases as the accelerator pedal increases to wide open throttle (WOT).

P0121

DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0335, or P0336 is not set.
The engine speed is between 400-7,000 RPM.
The engine coolant temperature (ECT) is between 69-127°C (156-260°F).
The intake air temperature (IAT) is between -20 to +125°C (-4 to +257°F).
The DTC runs continuously when the above conditions are met.

P0122, P0123, P0222, P0223

DTC P06A3 is not set.
The ignition is ON, or the engine is running.
The engine is not operating in reduced power mode.
The ignition voltage is greater than 6 V.
The DTCs runs continuously when the above condition are met.

P2135

DTCs P0121, P0122, P0123, P0222, P0223, or P06A3 are not set.
The ignition is ON, or the engine is running.
The engine is not operating in reduced power mode.
The ignition voltage is greater than 6 V.
The DTCs runs continuously when the above conditions are met.

The ECM detects that the TP sensor 1 voltage is stuck in range for less than 1 s.

P0122

The ECM detects that the TP sensor 1 voltage is less than 0.3 V for less than 1 s.

P0123

The ECM detects that the TP sensor 1 voltage is greater than 4.8 V for less than 1 s.

P0222

The ECM detects that the TP sensor 2 voltage is less than 0.3 V for less than 1 s.

P0223

The ECM detects that the TP sensor 2 voltage is greater than 4.6 V for less than 1 s.

The ECM detects that TP sensor 1 and TP sensor 2 disagree greater than 7-10 percent for less than 1 s.

P0121

DTC P0121 is a type B DTC.
The ECM commands the throttle actuator control (TAC) system to operate in a Reduced Engine Power mode.

P0122, P0123, P0222, P0223, or P2135

DTC P0122, P0123, P0222, P0223, and P2135 are type A DTCs.
The ECM commands the throttle actuator control (TAC) system to operate in a Reduced Engine Power mode.

Conditions for Clearing the DTC

DTC P0121 is a type B DTC.
DTCs P0122, P0123, P0222, P0223 and P2135 is a type A DTC.

If the Throttle Sweep Test is not available on the scan tool, observe the scan tool TP Sensor 1 and 2 Agree/Disagree parameter while performing the following tests: Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. The TP Sensor 1 and 2 Agree/Disagree parameter should display Agree. If Disagree is displayed, continue diagnosis in Circuit/System Testing.
A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.

Schematic Reference

Connector End View Reference

Throttle Actuator Control (TAC) System Description

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool. Verify DTC P06A3 is not set. If the DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM, LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0452-dtc-p124dp1249) .
Ignition ON, observe both TP Sensor voltage parameters with a scan tool. Verify the scan tool TP sensor parameters are between 1.0-4.0 V and change with accelerator pedal input.
Perform the Throttle Sweep Test while observing the TP Sensor 1 and 2 Agree/Disagree parameter with a scan tool. The TP Sensor 1 and 2 Agree/Disagree parameter should display Agree.
Observe the DTC Information with a scan tool. DTCs P0121, P0122, P0123, P0222, P0223, and P2135 should not set.
Observe both TP Sensor percentage parameters while quickly pressing the accelerator pedal from a closed throttle to WOT. Both TP Sensor percentage parameters should change.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the throttle body assembly.
Ignition OFF for 1 minute, test for less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the ECM.
Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal E and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Test for less than 1 V between the TP sensor 1 signal circuit terminal D and ground. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Test for 4.8-5.2 V between the TP sensor 2 signal circuit terminal F and ground. If less than specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Install a 3 A fused jumper wire between TP sensor 1 signal circuit terminal D and the 5-volt reference circuit terminal E. Verify the scan tool TP sensor 1 voltage parameter is greater than 4.8 V. If less than the specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.
If all circuits test normal, test or replace the throttle body assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Throttle Body Assembly Replacement (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5-Volt Reference	P0122, P0222, P0698	P0121, P0122, P0221, P0222, P0697, P2119, P2101	P0123, P0223, P0699, P2101, P2119	P0121, P0221, P0697, P0698, P0699
TP Sensor Signal 1	P0122	P0121, P0122, P2101, P2119	P0123	P0121, P0221, P2119
TP Sensor Signal 2	P0222	P0221, P0223	P0223, P0638, P2128, P2138	P0221
Low Reference		P0121, P0123, P0221, P0223, P2119, P2100	P0123, P0223*	P0121, P0221
* Internal ECM or TP sensor damage may occur if the circuit is shorted to B+

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: The engine is operating in closed loop Parameter Normal Range: TP Position Sensor 5%/4.2 V
5 V Reference	124%/0.0 V	7%/0.0 V	113%/TP 1 4.98, TP 2, 4.50 V
TP Sensor Signal 1	4%/0.00 V	7%/0.00 V	7%/0.00 V
TP Sensor Signal 2	4%/0.00 V	4%/4.98 V	27%/4.98 V
Low Reference		0%/4.98 V

TP Sensor

The throttle body assembly contains 2 throttle position sensors. The TP sensors are mounted to the throttle body assembly and are not serviceable. The TP sensors provide a signal voltage that changes relative to throttle blade angle. The Engine Control Module (ECM) supplies the TP sensors with a common 5 V reference circuit, a common low reference circuit, and two independent signal circuits. The TP sensors have opposite functionality. TP sensor 1 signal voltage decreases from greater than 4 V at idle to less than 1 V at wide open throttle (WOT). TP sensor 2 signal voltage increases from less than 1 V at idle to greater than 4 V at WOT.

The ignition voltage is greater than 7 V.
The ignition is ON, with the engine OFF, or the engine is operating.
DTC P0121 runs continuously once the above conditions are met.

The TP sensor 1 disagrees greater than 9 percent from TP sensor 2, or TP sensor 1 disagrees greater than 9 percent from the predicted value for greater than 1 s.

The ECM detects the TP sensor 1 signal voltage is less than 0.18 V for greater than 1 s.

The ECM detects the TP sensor 1 signal voltage is greater than 4.6 V for greater than 1 s.

P0221

The TP sensor 2 disagrees greater than 9 percent from TP sensor 1, or TP sensor 2 disagrees greater than 9 percent from the predicted value for greater than 1 s.

The ECM detects the TP sensor 2 signal voltage is less than 0.16 V for greater than 1 s.

The ECM detects the TP sensor 2 signal voltage is greater than 4.9 V for greater than 1 s.

DTCs P0121 and P0221 are Type B DTCs.
DTCs P0122, P0123, P0222, and P0223 are Type A DTCs.

DTCs P0121 and P0221 are Type B DTCs.
DTCs P0122, P0123, P0222, and P0223 are Type A DTCs.

If there is a condition with the TP sensors the ECM defaults to reduced power mode for the entire ignition cycle, even if the condition is corrected.

Schematic Reference

Connector End View Reference

Throttle Actuator Control (TAC) System Description

Description and Operation

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, verify that DTC P0697, P0698, or P0699 is not set. If a DTC is set, refer to «DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0452-dtc-p124dp1249) .
Clear the DTC Info with a scan tool.
Start the engine, observe the scan tool Throttle Position Sensor 1 and 2 voltage parameters. TP sensor 1 should be between 0.17-4.6 V and TP sensor 2 should be between 0.15-4.8 V.
Observe the scan tool Throttle Position sensor 1 and 2 parameters while performing the tests listed below. The parameter should display Agree. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.
Observe the DTC Information with a scan tool. DTCs P0121, P0122, P0123, P0221, P0222, and P0223 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at throttle body.
Ignition OFF, remove the fuse that supplies B+ to terminal 56 X2 of the ECM.
Test for less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the Engine Control Module.
Install fuse that supplies B+ to terminal 56 X2 of the ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal E and ground. If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the Engine Control Module. If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the Engine Control Module.
Ignition ON, verify that the scan tool Throttle Position Sensor 1 voltage parameter is less than 0.3 V. If greater than the specified value, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the Engine Control Module.
Connect a 3 A fused jumper wire between the 5 V reference circuit terminal E and the TP sensor 1 signal circuit terminal D. Verify the scan tool Throttle Position Sensor 1 voltage parameter is greater than 4.89 V. If less than the specified value, test the signal circuit for an open/high resistance or for a short to ground. If the circuit tests normal, replace the Engine Control Module.
Verify the scan tool Throttle Position Sensor 2 voltage parameter is greater than 4.97 V. If less than the specified value, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the Engine Control Module.
Connect a 3 A fused jumper wire between the TP sensor 2 signal circuit terminal F and the low reference circuit terminal C. Verify the scan tool Throttle Position Sensor 2 voltage parameter is less than 0.10 V. If greater than the specified value, test the signal circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the Engine Control Module.
If all circuits test normal, replace the throttle body assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Throttle Body Assembly Replacement (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of air flow into an engine is proportional to the amount of heat an engine generates. The ECM monitors the amount of air flow into the engine to calculate engine coolant temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the closed loop temperature or to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the closed loop temperature, diagnostics that use the ECT as enabling criteria, may not run when expected.

P0128

Before the ECM can report DTC P0128 failed, DTC P0117 and P0118 must run and pass.
DTCs P0100, P0101, P0102, P0103, P0111, P0112, P0113, P0116, P0117, P0118, P0119, or P0700 is not set.
The engine speed is greater than 760 RPM.
The ECT is colder than 70°C (158°F) at start up.
The vehicle speed is greater than 8 km/h (5 mph).
The air flow coming into the engine has accumulated to greater than 1,000 grams.
DTC P0128 runs continuously once the above conditions have been met for approximately 15 minutes. OR
DTCs P0116, P0117, P0118, or P0119 is not set.
The engine speed is greater than 25 RPM.
The block heater is not detected.
DTC P0128 runs continuously once the above conditions have been met for approximately 8 minutes

The ECM detects that the actual engine coolant temperature is 11°C (20°F) colder than the calculated thermostat regulating temperature of 89°C (192°F), for greater than 4 seconds or for a cumulative of 30 seconds. OR
The ECM detects that the actual engine coolant temperature is 10°C (18°F) colder than the calculated ECT for greater than 1 second or a cumulative of 10 seconds.

DTC P0128 is a Type B DTCs.

An engine that soaks for about 8 hours will help diagnosis the condition. After the cold soak, operate the vehicle at highway speeds for 20 minutes while monitoring the scan tool Calculated ECT - Thermostat parameter. If there is a condition, the calculated temperature will be 10°C (18°F) warmer than the actual engine coolant temperature.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Verify that the engine coolant level is correct. If the engine coolant is not at the correct level, refer to «Loss of Coolant»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
Verify that the engine coolant temperature is at the normal operating temperature. If the engine coolant temperature is colder than the normal operating temperature, refer to «Thermostat Diagnosis»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis-lsa) .
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Ignition OFF, remove the fuse that supplies B+ to circuit terminal X2-56 of the K20 ECM.
Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than specified value, test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to circuit terminal X2-56 of the K20 ECM.
Ignition ON, observe the scan tool the ECT sensor parameter. Verify that the ECT sensor parameter is at -40°C (-40°F). If warmer than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the K20 ECM.
Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT sensor parameter is warmer than 142°C (288°F). If colder than the specified value, test the signal circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
If all circuits test normal, test or replace the B34 ECT sensor.

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5 % of the specification. If not within the specified range, replace the B34 ECT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Engine Coolant Temperature Sensor Replacement (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Before the ECM can report DTC P0128 failed, DTC P0117 and P0118 must run and pass.
DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0114, P0116, P0117, P0118, P0121, P0122, P0123, P0502, or P0503 is not set.
The Engine has not run for greater than 30 minutes.
The Engine run time from a cold start is greater than 2 minutes.
The ECT is colder than 50°C (122°F) at start up.
The vehicle speed is greater than 8 km/h (5 mph) for more than 2.4 km/h (1.5 miles).
The Ethanol content of the fuel is less than 87 percent.
DTC P0128 runs continuously once the above conditions have been met for approximately 15 min. OR
DTCs P0116, P0117, or P0118 is not set.
The block heater is not detected.
DTC P0128 runs continuously once the above conditions have been met for approximately 8 min.

The ECM detects that the actual engine coolant temperature is 11°C (20°F) colder than the calculated thermostat regulating temperature of 89°C (192°F), for greater than 4 s or for a cumulative of 30 s. OR
The ECM detects that the actual engine coolant temperature is 10°C (18°F) colder than the calculated ECT for greater than 1 s or a cumulative of 10 s.

DTC P0128 is a Type B DTCs.

An engine that soaks for about 8 h will help diagnosis the condition. After the cold soak, operate the vehicle at highway speeds for 20 min while monitoring the scan tool Calculated ECT - Thermostat parameter. If there is a condition, the calculated temperature will be 10°C (18°F) warmer than the actual engine coolant temperature.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Verify that the engine coolant level is correct. If the engine coolant is not at the correct level, refer to «Loss of Coolant»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) .
Verify that the engine coolant temperature is at the normal operating temperature. If the engine coolant temperature is colder than the normal operating temperature, refer to «Thermostat Diagnosis (LF1, LY7)»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__thermostat-diagnosis-lf1-llt) .
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Test for less than 5 ohms between the low reference circuit terminal 2 and ground. If greater than specified value, test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Ignition ON, observe the scan tool the ECT sensor parameter. Verify that the ECT sensor parameter is at -40°C (-40°F). If warmer than the specified value, test the signal circuit for a short to ground. If the circuit/connections test normal, replace the K20 ECM.
Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECT sensor parameter is warmer than 142°C (288°F). If colder than the specified value, test the signal circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the K20 ECM.
If all circuits test normal, test or replace the B34 ECT sensor.

Ignition OFF, disconnect the harness connector at the B34 ECT sensor.
Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the «Temperature Versus Resistance - Engine Coolant Temperature Sensor»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__temperature-versus-resistance-engine-coolant) table and verify that the resistance is within 5 % of the specification. If not within the specified range, replace the B34 ECT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Engine Coolant Temperature Sensor Replacement (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean. The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. Or, to detect if the HO2S signal voltage switches at the same rate at which the ECM is commanding the heater ON and OFF.

Condition 1 and 2

Before the ECM can report that DTC P0130 or P0150 failed, DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0133, P0135, P0153, and P0155 must run and pass.
DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The engine is greater than 240 RPM.
The ignition voltage is greater than 10 volts.
The HO2S 1 heater duty cycle is greater than 90 percent for greater than 5 seconds.
The DTCs run continuously once the conditions above exist for greater than 60 seconds.

Condition 3

Before the ECM can report that DTC P0130 or P0150 failed, DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0133, P0135, P0153, and P0155 must run and pass.
The engine is operating.
The ignition voltage is greater than 10 volts.
The air flow into the engine has exceeded 10 grams.
The HO2S 1 heater duty cycle is greater than 70 percent or, the calculated exhaust gas temperature is warmer than 600°C (1,112°F).
Closed loop fuel control is enabled.
The evaporative emissions system (EVAP) is not performing an intrusive test.
The DTCs run continuously once the conditions above exist for greater than 30 seconds.

Condition 1

The ECM detects that the HO2S 1 signal voltage increases to greater than 2 volts within 4 ms of 4 out of 6 HO2S heater switch OFF samples.

Condition 2

The HO2S 1 voltage is between 520-1,150 mV and the corresponding HO2S 2 voltage is less than 100 mV.

The HO2S 1 voltage is between 60-400 mV and the corresponding HO2S 2 voltage is less than 500 mV.

DTCs P0130 and P0150 are Type B DTCs.

The HO2S 1 voltage should be between 350-550 mV with the ignition ON. If the voltage is greater than the specified value, there is a condition with the HO2S 1 circuits. If the voltage does not change after disconnecting the HO2S, the condition is between the sensor and the ECM. If the voltage is between 350-550 mV after disconnecting the sensor, the condition is with the HO2S 1.
Inspect the HO2S 1 harness connector for water intrusion. Moisture in a connector may cause voltage to bleed to other circuits within the connector.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the appropriate scan tool HO2S 1 voltage parameter. The HO2S 1 voltage parameter should be less than 1,025 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S 1.
Ignition ON, verify that the scan tool HO2S 1 voltage parameter is between 350-500 mV. If greater than the specified range, test the signal circuit terminal B of the HO2S for a short to the heater circuit terminal E. If the circuit/connections test normal, replace the ECM.
If all circuits/connections test normal, replace the appropriate HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140	P0138	P0140
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160	P0158	P0160
Low Reference		P0134, P0135, P0154, P0155

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Fluctuates above and below 350-500 mV
Sensor Signal	0-60 mV	445-450 mV	1275 mV
Low Reference		445-480 mV	1275 mV

HO2S 1 or 2

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of about 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

DTC P0201, P0202, P0203, P0204, P0205, P0206 P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The air flow into the engine is greater than 220 grams.
The HO2S 1 heater duty cycle is greater than 90 percent for greater than 5 seconds.
The evaporative emissions system (EVAP) is not performing an intrusive test.
The ECM is not commanding the air/fuel mixture lean.
DTC P0131 and P0151 run continuously once the conditions above exist for greater than 5 seconds.

DTC P0116, P0117, P0118, P0119, P0201, P0202, P0203, P0204, P0205, P0206 P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The conditions for a cold start are present.
The HO2S 1 heater duty cycle is greater than 90 percent.
DTC P0131 and P0151 run continuously once the conditions above exist for greater than 5 seconds.

The ECM detects that an HO2S 1 signal voltage is less than 60 mV while the corresponding HO2S 2 voltage is greater than 500 mV.

The ECM detects that an HO2S 1 signal voltage is less than 60 mV after a cold start.

DTCs P0131 and P0151 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine idling, observe the appropriate scan tool HO2S 1 voltage parameter. The voltage should fluctuate above and below the range of 350-550 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S 1.
Ignition ON, verify that the scan tool HO2S 1 voltage parameter is between 350-500 mV. If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
Verify that the following conditions do not exist: Lean condition. Low fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Exhaust leaks near the HO2S. Engine vacuum leaks. If you find any of the above conditions, repair as necessary.
If all circuits/connections test normal, replace the appropriate HO2S 1.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
HO2S High Signal	P0131, P0137, P0151, P0152, P0157	P0131, P0132, P0137, P0151, P0152, P0157, P2A00, P2A03	P0132, P0137, P0138, P0140, P0152, P0158, P0160	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P2A00, P2A03
HO2S Low Signal	P0131, P0137, P0151, P0157	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P0131, P0132, P0138, P0151, P0152, P0158, P2A00, P2A03	P0132, P0138, P0140, P0152, P0154, P0158, P0160	P2A00, P2A03

Circuit	Short to Ground	Open	Short to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal	0.00 V	Approximately 1.27 V	Approximately 1.27 V
HO2S Low Signal	0.00 V	Approximately 1.27 V	Approximately 1.27 V

HO2S Sensor 1 Voltage, HO2S Sensor 2 Voltage

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

P0131, P0137, P0151, or P0157

DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
The engine is operating in Closed Loop.
The Ignition 1 voltage is between 10-32 V.
The fuel level is greater than 10 %.
The throttle position (TP) is between 3-70 %.
The DTCs run continuously when the above conditions are met for 2 s.

P0132, P0138, P0152, or P0158

DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
The engine is operating in Closed Loop.
The Ignition 1 voltage is between 10-32 V.
The fuel level is greater than 10 %.
The throttle position (TP) is between 0-70 %.
The DTCs run continuously when the above conditions are met for 3 s.

P2A00 or P2A03

DTCs P0030, P0036, P0053, P0054, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1516, P2101, P2119, P2135, P2176 are not set.
The engine is running.
The system voltage is between 10-32 V.
The ECT Sensor parameter is more than 0°C (32°F).
DTCs P2A00 and P2A03 run continuously when the above conditions are met.

The ECM detects that the HO2S voltage is less than 50 mV.
The DTCs set within 50 s when the above condition is met.

The ECM detects that the HO2S voltage is greater than 1,050 mV.
The DTCs set within 50 s when the above condition is met.

The ECM detects that the Fuel Control Loop Status parameter is open.
DTCs P2A00 and P2A03 set within 30 s when the above condition is met.

DTCs P0131, P0132, P0137, P0138, P0151, P0152, P0158, P2A00 and P2A03 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Heated Oxygen Sensor Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool. Verify no B52 HO2S heater DTCs are set. If a B52 HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine running, observe the appropriate scan tool B52 HO2S voltage parameter. The reading should be within the range of 50-1,050 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the appropriate B52 HO2S harness connector.
Ignition ON, observe the appropriate scan tool HO2S voltage parameter. The parameter should display 1.27 V. If less than the specified range, test the high and low signal circuits for a short to ground. If both signal circuit test normal, replace the K20 ECM.
Ignition ON, test for 2.5-3.0 V between the high signal circuit terminal B and ground. If less than the specified range, test the high signal circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the high signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, connect a 3 A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A.
Ignition ON, verify the scan tool HO2S parameter displays 0.0 V. If greater than the specified range, test the low signal circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
If all circuits test normal, test or replace the appropriate B52 HO2S.

CAUTION

Refer to Heated Oxygen Sensor Resistance Learn Reset Caution .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140	P0138	P0140
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160	P0158	P0160
Low Reference		P0134, P0135, P0154, P0155

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Fluctuates above and below 350-500 mV
Sensor Signal	0-60 mV	445-450 mV	1275 mV
Low Reference		445-480 mV	1275 mV

HO2S 1 or 2

DTC P0201, P0202, P0203, P0204, P0205, P0206 P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The HO2S 1 heater duty cycle is greater than 90 percent for greater than 5 seconds.
The ECM is not commanding the air/fuel mixture rich.
DTC P0132 and P0152 run continuously once the conditions above exist for greater than 5 seconds.

The ECM detects that an HO2S 1 signal voltage is greater than 1,150 mV.

DTCs P0132 and P0152 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine idling, observe the appropriate scan tool HO2S 1 voltage parameter. The voltage should fluctuate above and below the range of 350-550 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition ON, verify that the scan tool HO2S voltage parameter is between 350-500 mV. If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
Install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
Verify that the following conditions do not exist: Leaking fuel injectors. High fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Restricted exhaust. If you find any of the above conditions, repair as necessary.
If all circuits/connections test normal, replace the appropriate HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140	P0138	P0140
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160	P0158	P0160
Low Reference		P0134, P0135, P0154, P0155

Conditions for Running the DTCs

Before the ECM can report that DTC P0133 or P0153 failed, DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0135, and P0155 must run and pass.
DTC P0036, P0037, P0038, P0057, P0058, P0130, P0137, P0138, P0140, P0141, P0150, P0157, P0158, P0160, P0161, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0442, P0443, P0455, P0458, P0459, P2096, P2097, P2098, P2099, P2177, P2178, P2179, P2088, P2089, P2090, P2232, P2235, P2270, P2271, P2272, or P2273 is not set.
The engine speed is 1,200-2,520 RPM.
The closed loop fuel control is enabled.
The engine load is 13-55 percent.
The exhaust gas temperature is warmer than 350°C (662°F).
The evaporative purge (EVAP) solenoid is commanded OFF, or is ON for greater than 10 seconds.
DTC P0133 and P0153 run continuously once the conditions above exist.

Conditions for Setting the DTCs

The ECM determines that the length of time for a primary HO2S to switch from lean to rich and back to lean, which is called a switching cycle, has exceeded a predetermined threshold. The condition exists for 2.5 cycles out of a 20 cycle test sample.

Action Taken when the DTCs Set

DTCs P0133 and P0153 are Type B DTCs.

Conditions for Clearing the MIL/DTCs

DTCs P0133 and P0153 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool DTC information. Verify no other DTC is not set. If any other DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine idling, observe the appropriate scan tool HO2S voltage parameter. The voltage should fluctuate above and below the range of 350-550 mV.
Observe the DTC information with a scan tool. DTCs P0133 and P0153 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Verify that none of the following conditions exist: Lean or rich condition. Water intrusion in the HO2S harness connector HO2S wiring harness damage Incorrect RTV sealant Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks near the HO2S Engine vacuum leaks Engine oil consumption Engine coolant consumption If you find any of the above conditions, repair as necessary.
If all conditions test normal, replace the appropriate HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
HO2S High Signal	P0131, P0137, P0151, P0152, P0157	P0131, P0132, P0137, P0151, P0152, P0157, P2A00, P2A03	P0132, P0137, P0140, P0152, P0158, P0160	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P0133, P0134, P013A, P013B, P013E, P013F, P0140, P0153, P0154, P0160, P1133, P1153, P2A00, P2270
HO2S Low Signal	P0131, P0137, P0151, P0157	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P0131, P0132, P0138, P0151, P0152, P0158, P2A00, P2A03	P0132, P0138, P0140, P0154, P0158, P0160	P2A00, P2A03

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

P0133, P0153, P1133, or P1153

DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
The engine coolant temperature (ECT) is greater than 71°C (159°F).
The intake air temperature (IAT) is warmer than -40°C (-40°F)
The ignition 1 voltage is between 10-32 V.
The fuel level is greater than 10 %.
The engine run time is greater than 60 s.
The engine speed is between 1,000-3,000 RPM.
The barometric (BARO) pressure is greater than 70 kPa.
The mass airflow (MAF) is between 15-55 g/s.
The fuel system is in Closed Loop.
The throttle position (TP) is greater than 5 %.
The DTCs run once per drive cycle when the above conditions are met.

P013A P013C, P013E, or P014A

Before the ECM can report DTC P013A, or P013C failed, DTCs P013E, P014A, P2270, and P2272 must run and pass.
Before the ECM can report DTC P013E, or P014A failed, DTCs P2270 and P2272 must run and pass.
DTCs P0030, P0036, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0120, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1174, P1516, P2101, P2119, P2135, P2176, P2270, P2271, P2A00 are not set.
The ignition 1 voltage is between 10-32 V.
The learned heater resistance is valid.
The fuel level is greater than 10 %.
The engine run time is equal to or greater than 5 min.
The accelerator pedal (APP) is steady.
The torque converter clutch (TCC) is applied.
The DTCs run once per ignition cycle, during decel fuel cut-off (DFCO), when the above conditions are met.

P013B P013D, P013F, or P014B

Before the ECM can report DTC P013B, or P013D failed, DTCs P013A, P013C, P013E, P013F, P014A, P014B, P2270, P2271, P2272, and P2273 must run and pass.
Before the ECM can report DTC P013F, or P014B failed, DTCs P013A, P013C, P013E, P014A, P2270, P2271, P2272, and P2273 must run and pass.
DTCs P0030, P0036, P0053, P0054, P0101, P0102, P0103, P0106, P0107, P0108, P0120, P0121, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P013A, P013B, P013E, P013F, P0140, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0300, P0442, P0443, P0446, P0449, P0455, P0496, P1133, P1174, P1516, P2101, P2119, P2135, P2176, P2270, P2271, P2A00 are not set.
The ignition 1 voltage is between 10-32 V.
The learned heater resistance is valid.
The fuel level is greater than 10 %.
The engine run time is equal to or greater than 5 min.
The DTCs run once per ignition cycle when the above conditions are met.

P0133 or P0153

The ECM detects that the HO2S 1 rich-to-lean or lean-to-rich average response time is greater than a calibrated value.
The DTCs set within 60 s when the above condition is met.

P013A or P013C

The ECM detects that the accumulated mass air flow monitored during rich-to-lean transitions between 450-150 mV is greater than 75 grams.

P013B or P013D

The ECM detects that the accumulated mass air flow monitored during lean-to-rich transitions between 350-650 mV is greater than 75 grams.

P013E or P014A

The ECM detects that the O2 sensor voltage has not decreased below 450 mV within 42 grams of accumulated air flow.

P013F or P014B

The ECM detects that the O2 sensor voltage has not increased above 350 mV within 200 grams of accumulated air flow.

P1133 or P1153

The ECM detects that the HO2S 1 rich-to-lean counts, or the lean-to-rich counts are less than a calibrated value.
The DTCs set within 60 s when the above condition is met.

DTCs P0133, P013A, P013B, P013C, P013D, P013E, P013F, P014A, P014B, P0153, P1133, and P1153 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
«Heated Oxygen Sensor Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool. Verify no B52 HO2S heater DTCs are set. If a B52 HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine running, observe the appropriate scan tool B52 HO2S voltage parameter. The reading should be within the range of 50-1,050 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Verify none of the following conditions exist: Lean or rich fuel injectors-Refer to «Fuel Injector Solenoid Coil Test (w/LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) Water intrusion in the B52 HO2S harness connector Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks near the B52 HO2S Engine vacuum leaks Engine oil consumption-Refer to «Oil Consumption Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-30l-or-36l-diagnostic-information-and-procedures__oil-consumption-diagnosis) Engine coolant consumption-Refer to «Loss of Coolant»(/cadillac/cts/ii-2007-2014/remont/cooling-system-mechanical/#engine-cooling-system__loss-of-coolant) If you find any of the above conditions, repair as necessary.
If all conditions test normal, test or replace the appropriate B52 HO2S.

CAUTION

Refer to Heated Oxygen Sensor Resistance Learn Reset Caution .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140	P0138	P0140
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160	P0158	P0160
Low Reference		P0134, P0135, P0154, P0155

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: Fluctuates above and below 350-500 mV
Sensor Signal	0-60 mV	445-450 mV	1275 mV
Low Reference		445-480 mV	1275 mV

Bank 1 or 2 HO2S 1

DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The HO2S 1 heater duty cycle is greater than 90 percent for more than 5 seconds.
DTCs P0134 and P0154 run continuously once the conditions above exist for greater than 10 seconds.

DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The HO2S 1 is warmed up for greater than 30 seconds.
The HO2S 1 heater duty cycle is greater than 68 percent.
DTCs P0134 and P0154 run continuously once the conditions above exist.

DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, or P216D is not set.
The ignition voltage is greater than 10 volts.
The engine speed is greater than 240 RPM.
The HO2S 1 is warmed up for greater than 30 seconds.
The calculated exhaust temperature is warmer than 600°C (1,112°F).
DTCs P0134 and P0154 run continuously once the conditions above exist.

The HO2S 1 signal voltage is between 400-520 mV, or 400-550 mV when the calculated exhaust temperature is warmer than 800°C (1,472°F).

The calculated internal resistance of the HO2S 1 is greater than 40,000 ohms when the calculated exhaust temperature is warmer than 600°C (1,112°F).

A corresponding HO2S 1 and HO2S 2 are greater than 200 mV during a decel fuel cut-off greater 3 seconds.

DTCs P0134 and P0154 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine idling, observe the appropriate scan tool HO2S voltage parameter. The voltage should fluctuate above and below the range of 350-550 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
Ignition OFF, connect a test lamp between the heater control circuit terminal D and B+.
Idle the engine, and verify the test lamp illuminates or flashes. If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Ignition ON, verify that the appropriate scan tool HO2S voltage parameter is between 350-500 mV. If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
Verify that none of the following conditions exist: The HO2S is loose Lean or rich condition. Water intrusion in the HO2S harness connector Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks near the HO2S Engine vacuum leaks If you find any of the above conditions, repair as necessary.
If all circuits/connections test normal, replace the appropriate HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
HO2S High Signal	P0131, P0137, P0151, P0157	P0132, P0133, P0134, P0137, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0157, P0160, P1133, P1153	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160	P0133, P0134, P013A, P013B, P013E, P013F, P0140, P0153, P0154, P0160, P1133, P1153, P2A00, P2270, P2271
HO2S Low Signal		P0131, P0132, P0133, P0134, P0138, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0158, P0160, P1133	P0131, P0132, P0133, P0134, P0138, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0158, P0160, P1133, P1153	P0134, P0138, P0140, P0154, P0158, P0160

Circuit	Short to Ground	Open	Short to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal	0.00 mV	Approximately 1.27 V	Approximately 1.27 V
HO2S Low Signal	0.00 mV	Approximately 1.27 V	Approximately 1.27 V

HO2S Sensor 1 Voltage, HO2S Sensor 2 Voltage

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.

DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
The ignition 1 voltage is between 10-32 V.
The engine run time is greater than 150 s.
The fuel system is in Closed Loop.
The DTCs run continuously when the above conditions are met.

P0134 or P0154

The ECM detects that the HO2S 1 voltage is between 350-550 mV.
The HO2S heater warm-up cycle is complete.
The DTCs set within 15 s when the above conditions are met.

P0140 or P0160

The ECM detects that the HO2S 2 voltage is not varying.
The HO2S heater warm-up cycle is complete.
The DTCs set within 15 s when the above conditions are met.

DTCs P0134, P0140, P0154, and P0160 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
«Heated Oxygen Sensor Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool. Verify no B52 HO2S heater DTCs are set. If a B52 HO2S heater DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine running, observe the appropriate scan tool B52 HO2S voltage parameter. The reading should be within the range of 50-1,050 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the appropriate B52 HO2S harness connector.
Ignition ON, observe the appropriate scan tool HO2S voltage parameter. The parameter should display 1.27 V. If less than the specified range, test the high and low signal circuits for a short to ground. If both signal circuits test normal, replace the K20 ECM.
Ignition ON, test for 2.5-3.0 V between the high signal circuit terminal B and ground. If less than the specified range, test the high signal circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the high signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, connect a 3 A fused jumper wire between the high signal circuit terminal B and the low signal circuit terminal A.
Ignition ON, verify the scan tool HO2S parameter displays 0.0 V. If greater than the specified value, test the low signal circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Verify none of the following conditions exist: Water intrusion in the HO2S harness connector Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks near the HO2S Engine vacuum leaks

If any of the above conditions exist, repair as necessary. If all circuits test normal, test or replace the appropriate B52 HO2S.

CAUTION

Refer to Heated Oxygen Sensor Resistance Learn Reset Caution .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition Voltage Supply - HO2S Bank 1 and 2 Sensor 1	P0030, P0031, P0050, P0051	P0050, P0051, P0134, P0135, P0154, P0155
Ignition Voltage Supply - HO2S Bank 1 and 2 Sensor 2	P0036, P0037, P0056, P0057	P0036, P0037, P0056, P0057, P0140, P0160
HO2S Bank 1 Sensor 1 Heater Control	P0031	P0030, P0134	P0032	P0135
HO2S Bank 1 Sensor 2 Heater Control	P0037	P0036, P0140	P0038	P0141
HO2S Bank 2 Sensor 1 Heater Control	P0051	P0050, P0154	P0052	P0155
HO2S Bank 2 Sensor 2 Heater Control	P0057	P0056, P0160	P0058	P0161

The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensor's rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground to maintain a desired temperature. The ECM controls the heater by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled up to voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

P0135 or P0155

Before the ECM can report DTC P0135 or P0155 failed, P0030, P0031, P0032, P0050, P0051, and P0052 must run and pass.
DTC P0130, P0131, P0132, P0134, P0150, P0151, P0152, or P0154 is not set.
The engine speed is greater than 240 RPM.
The ignition voltage is 10-18 volts.
The intake air temperature (IAT) is greater than -30°C (-22°F).
After the previous ignition cycle the engine OFF time was greater than 2 minutes, 0 seconds for LLT.
The calculated exhaust temperature is between 300-750°C (572-1,382°F).
The calculated exhaust temperature is colder than 750°C (1,382°F), for LLT.
The engine is not in decel fuel cut-off (DFCO).
The HO2S 1 is at operating temperature for greater than 10 seconds.
The internal HO2S 1 resistance is less than 10,000 ohms.
The HO2S 1 heater is enabled for greater than 120 seconds.
DTCs P0135 and P0155 run continuously once the above conditions are met for approximately 100 seconds.

P0141 or P0161

Before the ECM can report DTC P0141 or P0161 failed, DTCs P0036, P0037, P0038, P0056, P0057, and P0058 must run and pass.
DTCs P0137, P0138, P0140, P0157, P0158, or P0160 are not set.
The engine speed is greater than 240 RPM.
The ignition voltage is 10-18 volts.
The intake air temperature (IAT) is greater than -30°C (-22°F).
After the previous ignition cycle the engine OFF time was greater than 0 seconds.
The calculated exhaust temperature is 300-750°C (572-1,382°F), 300-700°C (572-1,292°F) for LLT.
The engine is not in decel fuel cut-off (DFCO).
The internal HO2S 2 resistance is less than 10,000 ohms.
The HO2S 2 heater is enabled for greater than 120 seconds.
DTCs P0141 and P0161 run continuously once the above conditions are met for approximately 100 seconds.

The ECM detects that the internal resistance of the HO2S 1 heater is not within the expected range for greater than 12 seconds.

The ECM detects that the internal resistance of the HO2S 2 heater is not within the expected range for greater than 6 seconds.

DTCs P0135, P0141, P0155, and P0161 are Type B DTCs.

Schematic Reference

Engine Controls Schematics (LLT) or Engine Controls Schematics (LF1)

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

With the engine at normal operating temperature, operate the engine above 1,200 RPM for 2 minutes and then allow the engine to idle. DTCs P0135, P0141, P0155, or P0161 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
Ignition OFF, connect a test lamp between the heater control circuit terminal D and B+. The test light should not illuminate. If the test lamp illuminates, test the heater control circuit for a short to ground. If the circuit/connections test normal, replace the ECM.
Idle the engine, verify the test lamp illuminates or flashes. If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Ignition ON, test for 2.0-3.0 V between the control circuit terminal D and ground. If not within the specified range, test the control circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
If all circuits/connections test normal, test or replace the HO2S.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Test for 5-25 ohms between terminals C and D of the HO2S. If not within the specified range, replace the HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140, P013A	P0138	P0140, P013A, P013E
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160, P013C	P0158	P0160, P013C, P014A
Low Reference		P0134, P0135, P0154, P0155

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Engine operating in Closed Loop. Parameter Normal Range: Fluctuates above and below 350-500 mV.
Sensor Signal	0-60 mV	400-455 mV	1275 mV
Low Reference		400-455 mV	1275 mV

Bank 1 or 2 HO2S 2

P0137 and P0157

DTC P0036, P0037, P0038, P0056, P0057, P0058, P0116, P0117, P0118, P0119, or P0128 is not set.
The engine speed is greater than 240 RPM.
The ignition voltage is greater than 10 volts.
The engine coolant temperature is colder than 40°C (104°F) at start-up and the engine coolant temperature was warmer than 60°C (140°F) when the ignition was turned OFF last ignition cycle.
The calculated exhaust temperature at the HO2S 2 is warmer than 700°C (1,292°F) and the HO2S 2 is warmed up for greater than 90 seconds.
The calculated exhaust temperature is colder than 800°C (1472°F) 5 seconds after engine start.
DTCs P0137 and P0157 run continuously once the above conditions are met.

P0138, P0140, P0158, and P0160

The engine speed is greater than 240 RPM.
The ignition voltage is greater than 10 volts.
The HO2S 2 heater duty cycle is stable and the HO2S 2 is warmed up for greater than 90 seconds.
The calculated exhaust temperature is colder than 800°C (1472°F).
DTCs P0138 and P0158 run continuously once the above conditions are met for greater than 5 seconds.
DTCs P0140 and P0160 run continuously once the above conditions are met for greater than 60 seconds.

P0137 or P0157

The ECM detects that a secondary HO2S signal voltage is less than 60 mV for greater than 1 seconds of for a cumulative of 10 seconds.

P0138 or P0158

The ECM detects that the HO2S signal voltage is greater than 1,150 mV for greater than 1 seconds or for a cumulative of 10 seconds.

The ECM detects that the HO2S 2 signal voltage is between 401-519 mV.
The ECM detects that the measured internal resistance of the HO2S 2 is greater than 40,000 ohms, when the calculated exhaust temperature is warmer than 500°C (932°F).
Either condition exists for greater than 1 second or for a cumulative of 10 seconds.

DTCs P0137, P0138, P0140, P0157, P0158, and P0160 are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Engine idling, observe the appropriate scan tool HO2S 2 voltage parameter. The reading should fluctuate above and below the range of 401-519 mV.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition ON, verify that the scan tool HO2S 2 voltage parameter is between 400-520 mV. If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
Verify that the following conditions do not exist: Lean, rich, or leaking fuel injectors. A fuel pressure that is too low or too high-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Evidence of water intrusion into the electrical connector of the HO2S The HO2S is loose Exhaust leaks near the HO2S Engine vacuum leaks If you find any of the above conditions, repair as necessary.
If all circuits/connections test normal, replace the appropriate HO2S sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
HO2S Bank 1 Sensor 1 Signal	P0131	P0134, P0135	P0132	P0133, P2096, P2097
HO2S Bank 1 Sensor 2 Signal	P0137	P0140, P013A	P0138	P0140, P013A, P013E
HO2S Bank 2 Sensor 1 Signal	P0151	P0154, P0155	P0152	P0153, P2098, P2099
HO2S Bank 2 Sensor 2 Signal	P0157	P0160, P013C	P0158	P0160, P013C, P014A
Low Reference		P0134, P0135, P0154, P0155

Before the ECM can reports that DTC P013A, P013C, P013E, or P014A failed, DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0135, and P0155 must run and pass.
DTC P0036, P0037, P0038, P056, P0057, P0058, P0137, P0138, P0140, P0141, P0157, P0158, P0160, P0161, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0442, P0443, P0455, P0458, P0459, P2096, P2097, P2098, P2099, P2177, P2178, P2179, P2088, P2089, P2090, P2232, P2235, P2270, P2271, P2272, or P2273 is not set.
The ignition voltage is greater than 10 volts.
The HO2S 1 and 2 are in closed loop.
The HO2S 2 resistance is less than 900 ohms.
The HO2S 2 has switched from lean to rich during the ignition cycle.
The calculated exhaust gas mass flow rate is greater than 2.22 g/s.
The calculated exhaust gas temperature for HO2S 2 is warmer than 450°C (842°F).
The HO2S 1 signal voltage is less than 141 mV
The HO2S 2 signal voltage is greater than 590 mV at the beginning of decel fuel cut-off - DTC P013E and P014A only.
The DTCs run continuously once the conditions above exist for greater than 4 seconds.

The ECM determines that the response time for the HO2S 2 to switch from greater than 400 mV to less than 200 mV is greater than 800 mS. The condition exists for greater than 4 seconds or for a cumulative time of 30 seconds.

The ECM determines the time for the HO2S 2 to transition from greater than 590 mV to less than 140 mV, during decel fuel cut-off is greater than 4 seconds. The condition exists for greater than 4 seconds or for a cumulative time of 30 seconds. OR
The ECM determines that the air flow into the engine exceeded 15 grams before the HO2S 2 transitions to less than 140 mV, during decel fuel cut-off. The condition exists for greater than 4 seconds or for a cumulative time of 30 seconds.

DTCs P013A, P013C, P013E, and P014A are Type B DTCs.

Schematic Reference

Connector End View Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool DTC information. Verify no other DTC is set. If any other DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine idling, observe the appropriate scan tool HO2S voltage parameter. The voltage should fluctuate above and below the range of 401-519 mV.
Observe the DTC information with a scan tool. DTC P013A, P013C, P013E, and P014A should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the harness connector at the appropriate HO2S.
Ignition ON, verify that the scan tool HO2S voltage parameter is between 400-520 mV. If less than the specified range, test the signal circuit terminal B for a short to ground. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A. Verify the scan tool HO2S voltage parameter is less than 60 mV. If greater than the specified range, test the low reference circuit for an open/high resistance or for a short to voltage. If the circuit/connections test normal, replace the ECM.
Verify that none of the following conditions exist: Lean or rich condition. Water intrusion in the HO2S harness connector HO2S wiring harness damage Incorrect RTV sealant Low or high fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Fuel saturation of the evaporative emission (EVAP) canister Exhaust leaks near the HO2S Engine vacuum leaks Engine oil consumption Engine coolant consumption If you find any of the above conditions, repair as necessary.
If all conditions test normal, replace the appropriate HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) controls a Closed Loop air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The ECM monitors the heated oxygen sensor (HO2S) signal voltage, and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The long term fuel trim values change in response to trends in the short term fuel trim The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. The ideal fuel trim values are around 0 %. A positive fuel trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

If the ECM detects an excessively lean condition, DTC P0171 or P0174 sets. If the ECM detects an excessively rich condition, DTC P0172 or P0175 sets.

DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0201-P0206, P0300-P0306, P0442, P0443, P0446, P0449, P0451-P0455, P0496, P0506, P0507, P2227-P2230, P2269 are not set.
The engine is in Closed Loop status.
The engine coolant temperature (ECT) is between -38 and +150°C (-36 and +302°F).
The intake air temperature (IAT) is between -38 and +150°C (-36 and +302°F).
The manifold absolute pressure (MAP) is between 5-255 kPa (1.45-37 psi).
The vehicle speed is less than 134 km/h (83 mph).
The engine speed is between 400-6,600 RPM.
The mass air flow (MAF) is between 0.5-510 g/s.
The barometric pressure (BARO) is greater than 70 kPa (10.2 psi).
The fuel level is greater than 10 %.
This diagnostic runs continuously when the above conditions have been met.

The average long term FT weighted average value is greater or less than a calibrated value.
The above condition is present for approximately 3 min after the Conditions for Running the DTC have been met.

DTCs P0171, P0172, P0174, and P0175 are Type B DTCs.

Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S value should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
The normal Short Term FT and Long Term FT parameters should be between +10 and -10 % with 0 % the optimum, with the engine running at operating temperature.
An HO2S will not cause this DTC to set without the occurrence of the circuit related HO2S DTCs. Do not replace an HO2S to address this DTC.
A fuel system delivery condition causes this DTC to set. Thoroughly inspect all items that cause a rich or a lean condition. Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) .
Any un-metered air into the engine causes this DTC to set. Thoroughly inspect all areas of the engine for vacuum leaks.
A MAF sensor condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor parameters will appear to be within range.
Inspect the air filter for being the correct one for this application. Make sure that the engine oil fill cap is in place and that it is tight. Verify that the engine oil dip stick is fully seated.

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Observe the DTC information with a scan tool. DTC P0171, P0172, P0174, or P0175 should not be set.
Engine running, observe the DTC information with a scan tool. Verify there are no HO2S DTCs set. If any HO2S DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Ignition ON, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to «Altitude Versus Barometric Pressure»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-specifications__altitude-versus-barometric-pressure) . If not the specified range, refer to «DTC P0106 (w/LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0008-dtc-p0118) .
Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The value should be between -20 % and +20 %. If not the specified range, inspect for the following: P0171 or P0174 A mass air flow (MAF) sensor signal that is skewed-If the Short Term FT parameters for both banks changes greater than 20 % when the MAF sensor is disconnected, refer to «DTC P0101 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0008-dtc-p0118) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Missing, restricted, or leaking exhaust components-Refer to «Symptoms - Engine Exhaust»(/cadillac/cts/ii-2007-2014/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . Malfunctioning fuel injectors-Refer to «Fuel Injector Solenoid Coil Test (w/LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Vacuum hoses for splits, kinks, and improper connections Insufficient fuel in the tank Low fuel pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings. The air induction system and the air intake ducts for leaks, or for a missing air filter element A cracked EVAP canister Evaporative pipes obstructed or leaking The crankcase ventilation system for leaks A mass air flow (MAF) sensor signal that is skewed-If the Short Term FT parameters for both banks changes greater than 20 % when the MAF sensor is disconnected, refer to «DTC P0101 (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0008-dtc-p0118) . Fuel contamination-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) . Missing, restricted, or leaking exhaust components-Refer to «Symptoms - Engine Exhaust»(/cadillac/cts/ii-2007-2014/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) . Malfunctioning fuel injectors-Refer to «Fuel Injector Solenoid Coil Test (w/LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) , The air intake duct for being collapsed or restricted The air filter for being dirty or restricted Objects blocking the throttle body The evaporative emissions control system for improper operation Excessive fuel in the crankcase-Change the oil as necessary.
If all conditions test normal, test the engine for a mechanical condition. Refer to «Symptoms - Engine Mechanical»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-30l-or-36l-diagnostic-information-and-procedures) .
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5 V Reference	P0641	P0641, P06A6	P0641	P06A6
Signal	P018C	P018B, P018C	P018D	P018B
Low Reference		P0641, P06A6		P06A6

The fuel pressure sensor is located on the fuel line. The fuel pressure sensor monitors the fuel pressure in the fuel line. The fuel pump control module monitors the voltage signal from the fuel pressure sensor.

The engine is running.
DTC P018C, P018D, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active.
DTC P0641 has not failed this ignition cycle.
Fuel pump control is enabled and the fuel pump control state is normal.
The engine has been running for at least 5 seconds.

The fuel pump control module does not detect a change in the fuel rail pressure of at least 30 kPa (4.4 psi) when the fuel pump is operating at its minimum or maximum voltage limits for over 5 seconds.

DTC P018B, P018C and P018D are Type A DTCs.

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Schematic Reference

Engine Controls Schematics (LLT) or Engine Controls Schematics (LF1)

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Note. Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC P0118B resets before proceeding with the circuit system testing. If the DTC does not reset, refer to Diagnostic Aids .

Ignition OFF, disconnect the harness connector at the B47 fuel pressure sensor.
Ignition OFF, test for less than 1 ohms between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.
Ignition ON, test for 4.8-5.2 V between the B47 fuel pressure sensor 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.
Verify the scan tool 5 V reference is less than 1 V. If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the K27 fuel pump flow control module.
Install a 3 A fused jumper wire between the signal circuit terminal 1 and the 5 V reference circuit terminal 3. Verify the scan tool 5 V reference is greater than 4.8 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump flow control module.
If all circuits test normal, replace the B47 fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions) or «Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5 V Reference Voltage	P0192, P0193, P0340, P0345, P0365, P0390, P0506, P0641, P2227, P2229	P0192	P0193, P0641, P2227, P2229	P0191
Fuel Rail Pressure Sensor Signal	P0192	P0192, P0193	P0193	P0191
Low Reference		P0193	P0193	P0191

The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail fuel pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

The engine speed is greater than 25 RPM for greater than 31 s.
DTC P0191 runs once an ignition cycle at engine start up when the condition has been met.

Condition 2 and 3

The engine speed is greater than 25 RPM for greater than 30 s.
The engine coolant temperature (ECT) at the previous engine shut down was warmer than 72°C (162°F).
The ECT at engine start is colder than 55°C (131°F).
At engine start, if the ECT is warmer than the intake air temperature (IAT), then the IAT must be within 35°C (95°F) of the ECT.
At engine start, if the IAT is warmer than the ECT, then the ECT must be within 10°C (50°F) of the IAT.
The block heater, if equipped, is not active.
The engine off time since the previous engine shut down is greater than 4.2 h.
DTC P0191 runs once an ignition cycle at engine start up when the above conditions have been met.

DTC P0087, P2187, or P2188 is set, and the fuel pressure at ignition ON is less than 120 kPa (17.4 psi) for greater than 4 s or for a cumulative of 30 s.

DTC P0088, P2177, or P2187 is set, and the fuel pressure at ignition ON is greater than 1.5 MPa (218 psi) for greater than 4 s or for a cumulative of 30 s.

The fuel pressure at ignition ON is greater than 1.5 MPa (218 psi) and a fuel pressure increase of greater than 385 kPa (56 psi) occurs during the fuel pump prime. The condition exists for greater than 4 s or for a cumulative of 30 s.

DTC P0191 is a Type A DTC.
A message center or an indicator may display Reduced Engine Power.

DTC P0191 is a Type A DTC.

A condition with the fuel tank fuel pump module or the fuel pump control module may set this DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Observe the scan tool DTC information, verify DTC P0627, P0628, P0629, P069E or U0109 is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine idling, observe the scan tool Fuel Rail Pressure Sensor parameter. The pressure should be approximately 1.9-2.1 Mpa (279-305 psi).
Engine idling, the scan tool Fuel Rail Pressure Sensor should be close to the scan tool Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
Move related harnesses/connectors of the B47 fuel rail fuel pressure sensor and verify the engine does not stumble, stall, or change engine speed. If the engine stumbles, stalls, or changes engine speed, test or repair the suspected harness or connection.
Observe the DTC information with a scan tool, DTC P0191 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the multi-way harness connector X109 at the rear of the intake manifold.
Remove the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 5 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal 12 and the 5 V reference circuit terminal 11. Verify the scan tool Fuel Rail Pressure Sensor Voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, remove the intake manifold.
Connect the multi-way harness connector X109.
Disconnect the B47 fuel rail fuel pressure sensor connector.
Remove the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance.
Install the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If greater than the specified range, test the 5 V reference circuit for a short to voltage.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground.
If all circuits test normal, replace the B47 fuel rail fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5 V Reference Voltage	P0193, P0642	P0193	P0193, P0643	P0191
Fuel Rail Pressure Sensor Signal	P0192	P0193	P0193	P0191
Low Reference		P0193		P0191

The engine speed is greater than 25 RPM for greater than 30 s.
DTC P0191 runs once an ignition cycle at engine start up when the condition has been met.

The engine speed is greater than 25 RPM for greater than 30 s.
The engine coolant temperature (ECT) at the previous engine shut down was warmer than 72°C (162°F).
The ECT at engine start is colder than 55°C (131°F).
At engine start, if the ECT is warmer than the intake air temperature (IAT), then the IAT must be within 35°C (63°F) of the ECT.
At engine start, if the IAT is warmer than the ECT, then the ECT must be within 10°C (18°F) of the IAT.
The block heater, if equipped, is not active.
The engine off time since the previous engine shut down is greater than 4.2 h.
DTC P0191 runs once an ignition cycle at engine start up when the above conditions have been met.

DTC P0087, P2187, or P2188 is set, and the fuel pressure at ignition ON is less than 120 kPa (17.4 psi) for greater than 4 s or for a cumulative of 30 s.

DTC P0088, P2177, or P2187 is set, and the fuel pressure at ignition ON is greater than 1.5 MPa (218 psi) for greater than 4 s or for a cumulative of 30 s.

The fuel pressure at ignition ON is greater than 1.5 MPa (218 psi) and a fuel pressure increase of greater than 350 kPa (51 psi) occurs during the fuel pump prime. The condition exists for greater than 4 s or for a cumulative of 30 s.

DTC P0191 is a Type A DTC.
A message center or an indicator may display Reduced Engine Power.

DTC P0191 is a Type A DTC.

A condition with the fuel tank fuel pump module or the fuel pump control module may set this DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Observe the scan tool DTC information, verify DTC P0627, P0628, P0629, P069E or U0109 is not set. If any of the DTCs are set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine idling, observe the scan tool Fuel Rail Pressure Sensor parameter. The pressure should be approximately 3.5-5.5 Mpa (508-798 psi).
Engine idling, the scan tool Fuel Rail Pressure Sensor should be close to the scan tool Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Fuel Rail Pressure Sensor should closely match each other.
Move related harnesses/connectors of the B47 fuel rail fuel pressure sensor and verify the engine does not stumble, stall, or change engine speed. If the engine stumbles, stalls, or changes engine speed, test or repair the suspected harness or connection.
Observe the DTC information with a scan tool, DTC P0191 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the multi-way harness connector X117 at the rear of the intake manifold.
Remove the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 5 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal 12 and the low reference circuit terminal 5. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter transitions from greater than 4.96 V to less than 0.02 V. If the parameter does not transition from the maximum to minimum value, test the signal circuit for an open/high resistance or a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, remove the intake manifold.
Connect the multi-way harness connector X117.
Disconnect the B47 fuel rail fuel pressure sensor connector.
Remove the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 1 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance.
Install the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If greater than the specified range, test the 5 V reference circuit for a short to voltage.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for a short to ground.
Connect a 3 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter transitions from greater than 4.96 V to less than 0.02 V. If the parameter does not transition from the maximum to the minimum value, test the signal circuit for an open/high resistance or a short to voltage.
If all circuits test normal, replace the B47 fuel rail fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5 V Reference Voltage	P0192, P0193, P0340, P0345, P0365, P0390, P0506, P0641, P2227, P2229	P0192	P0193, P0641, P2227, P2229	P0191
Fuel Rail Pressure Sensor Signal	P0192	P0192, P0193	P0193	P0191
Low Reference		P0193	P0193	P0191

The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the reference ground circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail fuel pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

The engine is running.
The ignition voltage is between 11-18 V.
The DTCs run continuously within the enabling conditions.

P0192

The ECM detects that the fuel rail fuel pressure sensor signal voltage is low.

P0193

The ECM detects that the fuel rail fuel pressure sensor signal voltage is high.

DTCs P0192 and P0193 are Type A DTCs.
A message center or an indicator may display Reduced Engine Power.

DTCs P0192 and P0193 are Type A DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool, DTC P0641 should not be set. If a DTC is set, refer to «DTC P0641, P0651, P0697, or P06A3 (ECM, LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0452-dtc-p124dp1249) .
Engine idling, observe the DTC information with a scan tool. DTC P0192 or P0193 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the multi-way harness connector X109 at the rear of the intake manifold.
Remove the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 5 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal 12 and the 5 V reference circuit terminal 11. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, remove the intake manifold.
Connect the multi-way harness connector X109.
Disconnect the B47 fuel rail fuel pressure sensor connector.
Remove the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance.
Install the fuse that supplies B+ to terminal 52-X1 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal A and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If greater than the specified range, test the 5 V reference circuit for a short to voltage.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is less than 0.02 V. If greater than the specified value, test the signal circuit for a short to voltage.
Connect a 3 A fused jumper wire between the signal circuit terminal B and the 5 V reference circuit terminal A. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for an open/high resistance or a short to ground.
If all circuits test normal, replace the B47 fuel rail fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5 V Reference Voltage	P0193, P0642	P0193	P0193, P0643	P0191
Fuel Rail Pressure Sensor Signal	P0192	P0193	P0193	P0191
Low Reference		P0193	P0193, P0643	P0191

The fuel rail fuel pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the reference ground circuit. The ECM receives a varying signal voltage on the signal circuit. The ECM monitors the voltage on the fuel rail fuel pressure sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low.

The ignition is ON or the engine is running.
The DTCs run continuously within the enabling conditions.

The ECM detects that the signal circuit voltage is less than 0.2 V for greater than 5 seconds.

The ECM detects that the signal circuit voltage is greater than 4.8 V for greater than 5 seconds.

DTCs P0192 and P0193 are Type A DTCs.
A message center or an indicator may display Reduced Engine Power.

DTCs P0192 and P0193 are Type A DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the DTC information with a scan tool, DTC P0641, P0642, or P0643 should not be set. If a DTC is set, refer to «DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0452-dtc-p124dp1249) .
Engine idling, observe the DTC information with a scan tool. DTC P0192 or P0193 should not set.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the multi-way harness connector X117 at the rear of the intake manifold.
Remove the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 5 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
Install the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 11 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
Connect a 3 A fused jumper wire between the signal circuit terminal 12 and the low reference circuit terminal 5. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter transitions from greater than 4.96 V to less than 0.02 V. If the parameter does not transition from the maximum to minimum value, test the signal circuit for an open/high resistance or a short to voltage. If the circuit tests normal, replace the K20 ECM.
Ignition OFF, remove the intake manifold.
Connect the multi-way harness connector X117.
Disconnect the B47 fuel rail pressure sensor connector.
Remove the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 1 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance.
Install the fuse that supplies B+ to terminal 56-X2 of the K20 ECM.
Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If greater than the specified range, test the 5 V reference circuit for a short to voltage.
Ignition ON, verify the scan tool Fuel Rail Pressure Sensor voltage parameter is greater than 4.96 V. If less than the specified value, test the signal circuit for a short to ground.
Connect a 3 A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Fuel Rail Pressure Sensor voltage parameter transitions from greater than 4.96 V to less than 0.02 V. If the parameter does not transition from the maximum to the minimum value, test the signal circuit for an open/high resistance or a short to voltage.
If all circuits test normal, replace the B47 fuel rail fuel pressure sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Short from Supply Circuit to Control Circuit
Direct Fuel Injector High Voltage Supply Cylinder 1	P2147	P0201	P2148	P1248
Direct Fuel Injector High Voltage Control Cylinder 1	P0261	P0201	P0262	P1248
Direct Fuel Injector High Voltage Supply Cylinder 2	P2150	P0202	P2151	P1249
Direct Fuel Injector High Voltage Control Cylinder 2	P0264	P0202	P0265	P1249
Direct Fuel Injector High Voltage Supply Cylinder 3	P2153	P0203	P2154	P124A
Direct Fuel Injector High Voltage Control Cylinder 3	P0267	P0203	P0268	P124A
Direct Fuel Injector High Voltage Supply Cylinder 4	P2156	P0204	P2157	P124B
Direct Fuel Injector High Voltage Control Cylinder 4	P0270	P0204	P0271	P124B
Direct Fuel Injector High Voltage Supply Cylinder 5	P216B	P0205	P216C	P124C
Direct Fuel Injector High Voltage Control Cylinder 5	P0273	P0205	P0274	P124C
Direct Fuel Injector High Voltage Supply Cylinder 6	P216E	P0206	P216F	P124D
Direct Fuel Injector High Voltage Control Cylinder 6	P0276	P0206	P0277	P124D

The engine control module (ECM) supplies voltage to each fuel injector on the injector high voltage supply circuits. The ECM energizes each fuel injector by grounding the high voltage control circuit of the fuel injector. The ECM monitors the status of the injector high voltage supply circuits and the fuel injector high voltage control circuits. When a fuel injector circuit condition is detected by the ECM, the affected fuel injector(s) is disabled.

The engine is running.
The ignition voltage is between 11-18 V.
The DTCs run continuously once the above conditions are met.

P0201, P0202, P0203, P0204, P0205, or P0206

The ECM detects the injector high voltage supply circuit or the injector high voltage control circuit is open for greater than 2 s.

P0261, P0264, P0267, P0270, P0273, or P0276

The ECM detects the injector high voltage control circuit is shorted to ground for greater than 2 s.

P0262, P0265, P0268, P0271, P0274, or P0277

The ECM detects the injector high voltage control circuit is shorted to voltage for greater than 2 s.

DTCs P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, and P0277 are Type A DTCs.

Performing the fuel injector coil test may help isolate an intermittent condition. Refer to «Fuel Injector Solenoid Coil Test (w/LF1)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) .
If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Control Circuit Status parameters. An Injector Control Circuit Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Connector End View Reference

Description and Operation

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Electrical Information Reference

«Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
«Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
«Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
«Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Observe the DTC information with a scan tool. DTC P0685 or P1682 should not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
Engine operating, observe the DTC information with a scan tool. DTC P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, or P0277 should not set.
Observe the scan tool Current Misfire Counter parameters. The Current Misfire Counters should not increment.
Ignition ON, observe the scan tool Cylinder 1-6 Injector Control Circuit Status parameters. Verify the Injector Control Circuit Status parameters display OK.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Ignition OFF, disconnect the appropriate multi-way harness connector X109 or X110, at the rear of the intake manifold.
Ignition ON, observe the appropriate scan tool Cylinder 1-6 Injector Control Circuit Status. The parameter should display Open. If not the specified value, test the appropriate high voltage supply circuit, ECM side, for a short to ground or the appropriate high voltage control circuit, ECM side, for a short to voltage. If the circuits test normal, replace the K20 ECM.
Ignition ON, connect a test lamp between the appropriate high voltage supply circuit and the high voltage control circuit. The Injector Control Circuit Status should transition from Open to OK. If not the specified value, test for the following conditions in the ECM side of the harness: An open/high resistance in the high voltage supply circuit An open/high resistance in the high voltage control circuit A short to ground in the high voltage control circuit A short to voltage in the high voltage supply circuit If the circuits test normal, replace the K20 ECM.
Ignition OFF, measure the resistance between the appropriate high voltage supply circuit and ground. The DMM should display OL ohms. If less than the specified range, test the high voltage supply circuit and the high voltage control circuit for a short to ground. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s).
Test for 2-3 ohms between the appropriate high voltage supply circuit and high voltage control circuit. If less than the specified range, test for a short between the high voltage supply circuit and high voltage control circuit. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector(s). If greater than the specified range, test the high voltage supply circuit and high voltage control circuit for an open/high resistance. If the circuits/connections test normal, test or replace the appropriate Q17 fuel injector.

Note. The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis.

Remove the intake manifold and disconnect the appropriate Q17 fuel injector.
Test for 1.9-2.3 ohms at 20°C (68°F) between the high voltage supply circuit terminal 2 and the high voltage control circuit terminal 1 at the Q17 fuel injector. If not within the specified range, replace the Q17 fuel injector.
Measure the resistance between each terminal at the Q17 fuel injector and the Q17 fuel injector housing/case. The DMM should display OL ohms. If less than the specified value, replace the Q17 fuel injector.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

«Fuel Injector Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions__fuel-injector-replacement)
«Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
«Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
Direct Fuel Injector High Voltage Supply Cylinder 1	P2146	P0201	P2146
Direct Fuel Injector High Voltage Control Cylinder 1	P0261	P0201	P0262
Direct Fuel Injector High Voltage Supply Cylinder 2	P2149, P216A	P0202	P2149, P216A
Direct Fuel Injector High Voltage Control Cylinder 2	P0264	P0202	P0265
Direct Fuel Injector High Voltage Supply Cylinder 3	P2152, P216D	P0203	P2152, P216D
Direct Fuel Injector High Voltage Control Cylinder 3	P0267	P0203	P0268
Direct Fuel Injector High Voltage Supply Cylinder 4	P2155	P0204	P2155
Direct Fuel Injector High Voltage Control Cylinder 4	P0270	P0204	P0271
Direct Fuel Injector High Voltage Supply Cylinder 5	P2149, P216A	P0205	P2149, P216A
Direct Fuel Injector High Voltage Control Cylinder 5	P0273	P0205	P0274
Direct Fuel Injector High Voltage Supply Cylinder 6	P2152, P216D	P0206	P2152, P216D
Direct Fuel Injector High Voltage Control Cylinder 6	P0276	P0206	P0277

The engine speed is greater than 80 RPM.
The ignition 1 signal parameter is between 10-18 V.
The injector has been commanded ON and OFF at least once.
The DTCs run continuously once the above conditions are met.

The ECM detects the injector high voltage supply circuit or the injector high voltage control circuit is open for greater than 4 seconds or for a cumulative of 30 seconds.

The ECM detects the injector high voltage control circuit is shorted to ground for greater than 4 seconds or for a cumulative of 30 seconds.

The ECM detects the injector high voltage control circuit is shorted to voltage for greater than 4 seconds or for a cumulative of 30 seconds.

P2146, P2149, P2152, P2155, P216A, or P216D

The ECM detects the injector high voltage supply circuit is shorted to ground or shorted to a voltage for greater than 4 seconds or for a cumulative of 30 seconds.

DTCs P0201, P0202, P0203, P0204, P0205, P0206, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277, P2146, P2149, P2152, P2155, P216A, and P216D are Type B DTCs.

The high voltage supply circuits of injectors 2 and 5, and injectors 3 and 6, are paired together with a dual high side driver in the controller. A short to ground, or a short to voltage, on one of the paired circuits will set a DTC for the companion injector. The ECM will also disable the high side driver for the affected injectors.
The high voltage supply circuits of injectors 1 and 4 are not paired together in the controller.
Performing the fuel injector coil test may help isolate an intermittent condition. Refer to «Fuel Injector Solenoid Coil Test (w/LLT)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) .
If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool Injector Control Circuit Test Status parameters. An Injector Control Circuit Test Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

Schematic Reference

Connector End View Reference

Description and Operation