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Engine Controls and Fuel - 6.2l - DTC p0685 - DTC p2635 Cadillac CTS II

Testing & Diagnostics ~11349 words

Diagnostic Instructions

  1. 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.
  2. 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.
  3. «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.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Battery Supply Voltage - CoilP0685P0685
Battery Supply Voltage - Armature
Relay Control CircuitP0685P0685, P1682P0685, P0690, P1682, P2101
Relay Feedback CircuitP0690

Typical Scan Tool Data

Display ParametersNormal RangeShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, with the engine OFF, powertrain relay commanded ON
Engine Controls Ignition Relay Control Circuit Test StatusOK/Not RunShort to GRD/OpenShort to GRD/OpenShort to B+
Engine Controls Ignition Relay CommandONONONON
Engine Controls Ignition Relay Feedback Signal12-12.9 V0.0 V0.0 V12-12.9 V

Engine Controls Ignition Relay Feedback Signal

Circuit/System Description

The engine controls ignition relay or powertrain relay is a normally open relay. The relay switch is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver. When the ECM commands the powertrain relay ON, ignition voltage is supplied to several fuses in the under-hood fuse block.

The ignition voltage that is supplied to the ECM through the powertrain relay provides power to the internal ECM circuits associated with the throttle actuator control (TAC) operation. The ECM also monitors the voltage level on the ignition voltage circuit to confirm that the powertrain relay contacts have closed.

Conditions for Running the DTC

  1. The ignition is ON.
  2. The ignition voltage is between 11-18 V.
  3. The DTC runs continuously when the above conditions are met.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 2 s.

P0690

  1. The ECM detects the engine controls ignition relay feedback circuit is greater than 2 V when the relay is commanded OFF.
  2. The ECM detects the engine controls ignition relay feedback circuit is greater than 18 V when the relay is commanded ON.
  3. The condition is present for greater than 2 s.

Action Taken When the DTC Sets

DTCs P0685 and P0690 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P0685 and P0690 are Type B DTCs.

Reference Information

Schematic Reference

  1. «Engine Controls Schematics»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-wiring-schematic-diagrams)
  2. «Power Distribution Schematics»(/cadillac/cts/ii-2007-2014/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Electrical Center Identification Views»(/cadillac/cts/ii-2007-2014/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)
  4. «Probing Electrical Connectors»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__probing-electrical-connectors)
  5. «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)
  6. «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

  1. Ignition ON, command the Engine Controls Ignition Relay ON and OFF with a scan tool while observing the following Engine Controls Ignition Relay control circuit status parameters: Engine Controls Ignition Relay Control Circuit Low Voltage Test Status Engine Controls Ignition Relay Control Circuit Open Test Status Engine Controls Ignition Relay Control Circuit High Voltage Test Status Each parameter should toggle between OK and Not Run or Not Run and OK.
  2. Ignition ON, view the DTC information with a scan tool. DTC P0685 or P0690 should not set.
  3. 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

Note. You must perform the Circuit/System Verification first.

  1. Ignition OFF, disconnect the KR75 powertrain relay.
  2. Verify a test lamp illuminates between both of the following relay battery voltage circuit terminals and ground: Terminal 85 Terminal 30 If the test lamp does not illuminate, test the relay battery voltage circuit for an open/high resistance or a short to ground.
  3. Ignition OFF, verify that a test lamp does not illuminate between the ignition voltage circuit terminal 87 and ground. If the test lamp illuminates, test the ignition voltage circuit for a short to voltage.
  4. Connect a 20 A fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch ignition voltage circuit terminal 87.
  5. Ignition ON, observe the scan tool Engine Controls Ignition Relay Feedback Signal parameter. The ECM should communicate, and the parameter should display 9-14 V. If not the specified range, or the ECM does not communicate, test the ignition voltage circuit between the powertrain relay and the ECM for a short to ground or for an open/high resistance. If the circuit/connections test normal, replace the K20 ECM.
  6. Ignition OFF, verify that a test lamp does not illuminate between the control circuit terminal 86 and B+. If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  7. Connect a DMM set to the diode setting between the control circuit terminal 86 and ground.
  8. Ignition ON, verify the DMM does not display OL. If the DMM displays OL, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  9. If all circuits test normal, replace the KR75 powertrain relay.

Component Testing

  1. Test for one of the following resistance specifications between terminals 85 and 86 of the KR75 powertrain relay: 70-110 ohms 200-250 ohms If not within the specified range, replace the KR75 powertrain relay.
  2. Test for infinite resistance between the following terminals of the KR75 powertrain relay: 30 and 86 30 and 87 30 and 85 85 and 87 If not the specified value, replace the KR75 powertrain relay.
  3. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87. If greater than the specified range, replace the KR75 powertrain relay.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «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
  1. 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.
  2. 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.
  3. «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 fuel pump control module uses the serial data network to signal the engine control module (ECM) that the fuel pump control module is requesting malfunction indicator lamp (MIL) illumination. A DTC is set in the fuel pump control module, and the request for MIL illumination is sent when the fuel pump control module determines that a failure that affects emissions has occurred in the fuel pump control system. When the ECM receives the message from the fuel pump control module, DTC P069E will set in the ECM.

The ignition is ON, or the engine is running.

Conditions for Setting the DTC

The fuel pump control module requests the ECM to illuminate the MIL.

  1. DTC P069E is a Type A DTC.
  2. DTC P069E will continue to be current or active as long as the fuel pump control module is requesting MIL illumination.

DTC P069E is a Type A DTC.

Diagnostic Aids

Communication codes, U-codes, as well as powertrain codes, P-codes, set in the fuel pump control module will cause the fuel pump control module to request DTC P069E to be set in the ECM.

DTC Type Reference

Scan Tool Reference

  1. DTC P069E is an informational DTC. If there are no engine controls or communication DTCs, 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) for diagnosis of fuel pump control module DTCs.
  2. 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.

  1. 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.
  2. 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.
  3. «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 of the diagnostic category.

The diagnostic trouble code (DTC) indicates that an emission related transmission DTC set in the transmission control module (TCM). The engine control module (ECM) receives the TCM information over the serial data circuit. The ECM turns ON the malfunction indicator lamp (MIL) when the TCM sends a message over the serial data circuit requesting MIL illumination. The DTC information for the ECM will only display DTC P0700, but the Freeze Frame/Failure Records data will display the transmission DTC that set.

  1. The ignition is ON or the engine is operating.
  2. DTC P0700 runs continuously.

The ECM receives a serial data message from the TCM requesting the ECM to turn ON the MIL lamp.

DTC P0700 is a Type A DTC.

Conditions for Clearing the MIL/DTC

DTC P0700 is a Type A DTC.

Communication codes, U-codes, as well as powertrain codes, P-codes, set in the TCM can cause the TCM to request DTC P0700 to be set in the ECM.

DTC Type Reference

Scan Tool Reference

  1. DTC P0700 is an informational DTC. If there are no engine controls or communication DTCs, 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) for diagnosis of TCM DTCs.
  2. 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.
  1. 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.
  2. 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.
  3. «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 Fuel Trim Cylinder Balance diagnostic detects a rich or lean cylinder to cylinder air/fuel ratio imbalance in each bank. The diagnostic monitors the pre-catalyst heated oxygen sensor (HO2S) signal's frequency and amplitude characteristics by calculating an accumulated voltage over a predetermined sample period. An imbalance is indicated when multiple samples of the accumulated voltage are consistently higher than the desired value.

  1. DTCs P0030, P0036, P0050, P0053, P0059, P0101, P0102, P0103, P0106, P0107, P0108, P0117, P0118, P0128, P0131, P0132, P0133, P0134, P0135, P0151, P0152, P0153, P0154, P0155, P0201-P0206, P0300, P0301-P0306, P0411, P0412, P0418, P0442, P0443, P0446, P0449, P0452, P0453, P0454, P0455, P0496, P1133, P1153, P1516, P2101, P2119, P2120, P2125, P2135, P2138, P2176, P2431, P2432, P2433, P2440, P2A00, P2A03 are not set.
  2. The device control is not active.
  3. The intrusive diagnostics are not active.
  4. The engine overspeed protection is not active.
  5. The power take-off (PTO) is not active.
  6. The traction control is not active.
  7. The fuel control is in air-fuel Closed Loop.
  8. The system voltage is more than 10 volts, or less than 18 volts.
  9. The engine run time is greater than 100 seconds.
  10. The engine coolant temperature (ECT) is greater than -20°C (-4°F).
  11. The engine speed is greater than 425 RPM, but less than 6,000 RPM.
  12. The mass air flow is greater than 25 g/s, but less than 510 g/s.

Multiple samples of the pre-catalyst HO2S accumulated voltage are consistently greater than the desired value.

DTCs P1174 and P1175 are Type B DTCs.

DTCs P1174 and P1175 are Type B DTCs.

  1. The fuel trim cylinder balance diagnostic is very sensitive to heated oxygen sensor (HO2S) design. A non-OE sensor or an incorrect part number may set a false DTC.
  2. Monitoring the misfire current counters, or misfire graph, may help to isolate the cylinder that is causing the condition.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Troubleshooting with a Test Lamp»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  3. «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)
  4. «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

  1. Read and record the Freeze Frame/Failure Records data taking note of the speed and load at which the DTC set.
  2. Diagnose any other DTCs that 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) .
  3. With the engine idling and the transmission in the Park or Neutral position, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor parameter should be between 19-42 kPa. If the MAP sensor parameter is not between 19-42 kPa, refer to «DTC P0106»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-dtc-p0016-dtc-p0208) or «DTC P0107 or P0108»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-dtc-p0016-dtc-p0208) .
  4. Inspect the air induction system for modified, damaged, leaking, or restricted components.
  5. Inspect the crankcase ventilation system for improper operation.
  6. Inspect the vacuum hoses for splits, kinks, and improper connections.
  7. Inspect for vacuum leaks at the intake manifold, the throttle body, and the injector O-rings.
  8. Test for a restricted, damaged, leaking, or modified exhaust system from the catalytic converter forward. Refer to «Symptoms - Engine Exhaust»(/cadillac/cts/ii-2007-2014/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  9. Test the fuel injectors for improper operation. Refer to «Fuel Injector Diagnosis (w/J39021 or w/Tech 2)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Diagnosis (w/CH47976)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) .
  10. Test for fuel contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) .
  11. Test for excessive fuel in the crankcase due to leaking injectors.
  12. Test the ignition system for improper operation. Refer to «Electronic Ignition System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) .
  13. Test the engine for any mechanical conditions such as sticking valves, lifters, etc., which could alter the flow into the combustion chamber. Refer to «Symptoms - Engine Mechanical»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verify the repair under the same speed and load as noted in the Freeze Frame/Failure Records data recorded during testing.

  1. 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.
  2. 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.
  3. «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 voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

The engine is running.

The fuel pump control module detects an over-temperature fault.

DTCs P064A and P1255 are Type A DTCs.

DTCs P064A and P1255 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

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

  1. Verify that DTC P0231, P0232 or P023F are not set. If any of those codes are set, refer to «DTC P0231, P0232, or P023F»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-dtc-p0231-dtc-p0454) .
  2. Ensure that the entire undercarriage of the vehicle is clean, especially around the area where the K27 fuel pump control module is located. Clear all codes from the K27 fuel pump control module and test drive the vehicle. Verify that DTC P1255 or P064A do not set. If DTC P1255 or P064A reset, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for fuel pump control module replacement, setup, and programming

  1. 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.
  2. 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.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

System Description

The engine control module (ECM) detects engine misfire by detecting variations in crankshaft deceleration between firing strokes. For accurate detection of engine misfire, the ECM must distinguish between crankshaft deceleration caused by actual misfire and deceleration caused by rough road conditions. The antilock brake system (ABS) can detect if the vehicle is on a rough road based on wheel acceleration/deceleration data supplied by the wheel speed sensors. If the ABS detects rough road above predetermined threshold, this information is sent to the ECM. The ECM uses the rough road information when calculating engine misfire. If the ABS is malfunctioning and cannot detect rough roads, the misfire diagnostic will continue to run; however, if an engine misfire DTC sets, this DTC also sets indicating that rough road data was not available, or there was no communication with the brake control module during the misfire calculation due to an ABS malfunction.

  1. The vehicle speed is greater than 8 km/h (5 mph).
  2. The engine speed is less than 8,192 RPM.
  3. The engine load is less than 60 %.
  4. Engine misfire is detected and DTC P0300 sets with the MIL illuminated.
  5. DTCs P1380 and P1381 run continuously when the above conditions are met.

P1380

  1. The ABS controller sends a message to the ECM indicating that a failure has occurred in the ABS module.
  2. Engine misfire is detected and DTC P0300 set.

P1381

  1. An ABS malfunction exists for more than 10 s, preventing the ECM from receiving rough road detection data.
  2. Engine misfire is detected and DTC P0300 set.

DTCs P1380 and P1381 are Type C DTCs.

DTCs P1380 and P1381 are Type C DTCs.

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Monitor the ABS DTCs on the scan tool.

  1. If any ABS DTCs are set, diagnose those first. 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) .
  2. If there are no ABS DTCs set, refer to «Symptoms - Antilock Brake System»(/cadillac/cts/ii-2007-2014/remont/anti-locktraction-control/#antilock-brake-system-with-traction-control-system-stability-control-system__symptoms-antilock-brake-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. 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.
  2. 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.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The catalytic converter must be warmed to efficiently reduce the emissions. The cold start strategy is to reduce the amount of time it takes to warm the catalytic converter. During a cold start, the engine idle speed is elevated and spark timing is retarded to allow the catalyst to warm quickly. This diagnostic monitors the following to build an exhaust energy model

  1. Engine speed
  2. Spark advance
  3. Throttle position
  4. Engine airflow
  5. Engine coolant temperature
  6. Engine runtime
  7. Park/neutral position
  8. Vehicle speed

The actual model is then compared to the expected exhaust energy model.

  1. The engine is running, and a cold start has been detected.
  2. Vehicle speed is less than 2 km/h (1 mph).
  3. The engine is at idle with no input from the accelerator pedal.
  4. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0220, P0222, P0223, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0335, P0336, P0351, P0352, P0353, P0501, P0502, P0506, P0507, P0601, P0602, P0603, P0604, P0606, P0607, P060D, P062F, P0641, P0651, P1101, P1516, P1682, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, P2176, P2610 are not set.

This DTC runs for 15 seconds within the first 2 minutes of start-up. This diagnostic runs once per trip when a cold start has been determined.

The actual exhaust energy model does not match the expected exhaust energy model.

DTC P1400 is a Type A DTC.

DTC P1400 is a Type A DTC.

Description and Operation

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Any loading of the engine that lowers engine RPM, such as with partial application of the clutch, A/C cycling etc., during the first 120 seconds of engine run time may set this DTC.

  1. Allow the engine to cool.
  2. Start and idle the engine for at least 2 minutes.
  3. DTC P1400 should run and pass.
  1. Inspect the air intake system for the following: Damage, restriction, or modification Dirty or deteriorating air filter element Crankcase ventilation system for correct operation-Refer to «Crankcase Ventilation System Inspection/Diagnosis»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures__crankcase-ventilation-system-inspectiondiagnosis) . Water intrusion Vacuum leak and other un-metered air downstream of the mass air flow (MAF) sensor Intake manifold leak
  2. Inspect the exhaust system for the following: Water intrusion Exhaust leak Damaged, restricted, modified or enhanced exhaust system-Refer to «Symptoms - Engine Exhaust»(/cadillac/cts/ii-2007-2014/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  3. Inspect the engine mechanical for items that could alter the air flow into the combustion chamber. Refer to «Symptoms - Engine Mechanical»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
TAC Motor Control ClosedP1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176
TAC Motor Control OpenP1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176P1516, P2101, P2176

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.

P1516 and P2101

  1. DTC P0606 and P1682 is not set.
  2. The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
  3. The engine is running or the following conditions are met: The engine is not running. The ignition voltage is greater than 11 V. The TAC system is not in the Battery Saver mode. The ECM is commanding the throttle. The ECM has learned the minimum throttle position.
  4. DTC P1516 and P2101 run continuously when the above conditions are met.

P2119

  1. The ignition is ON.
  2. The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
  3. The TP sensor 1 voltage is greater than 1.7 V
  4. The ECM is not commanding the throttle blade.
  5. DTC P2119 runs continuously when the above conditions are met.

P2176

  1. DTCs P0120, P0121, P0122, P0123, P0220, P0222, P0223, or P1682 is not set.
  2. The ignition is ON.
  3. The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
  4. The ECM enable the minimum throttle learn procedure.
  5. DTC P2176 run continuously when the above conditions are met.

P1516

The actual throttle position does not match the predicted throttle position for greater than 0.2 s.

P2101

The actual throttle position does not match the predicted throttle position for greater than 0.2 s.

The ECM detects that the throttle blade did not return to the default position when the TAC motor is de-energized for greater than 0.5 s.

The ECM detects that both throttle position (TP) sensors were greater than a predetermined voltage during the minimum throttle learn procedure for greater than 2 s.

P1516, P2101, and P2176

  1. DTCs P1516, P2101, and P2176 are Type A DTCs.
  2. The control module commands the TAC system to operate in the Reduced Engine Power mode.
  3. A message center or an indicator displays Reduced Engine Power.
  4. Under certain conditions, the control module commands the engine OFF.
  1. DTC P2119 is a Type C DTC.
  2. The driver information center, if equipped, may display a message.
  1. DTCs P1516, P2101, and P2176 are Type A DTCs.
  2. DTC P2119 is a Type C DTC.
  1. If the Throttle Sweep Test is not available on the scan tool, observe the scan tool TAC Motor 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 TAC Motor parameter should display Enabled. If Disabled is displayed, continue diagnosis in Circuit/System Testing.
  2. Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close.
  3. A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.
  4. A low battery condition may cause a DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

  1. Ignition ON, observe the DTC information with a scan tool. DTC P0120, P0122, P0123, P0220, P0222, P0223, P0562, P0621, P0622, or P2135 should not set. If a DTC sets, 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) for further diagnosis.
  2. Clear the DTCs with a scan tool. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
  3. Ignition ON, observe the scan tool TAC Motor parameter. The reading should display Enabled.
  4. Observe the DTC information with a scan tool. DTC P1516, P2101, P2119, or P2176 should not set.
  5. Perform the Throttle Sweep Test while observing the TAC Motor parameter with a scan tool. The TAC Motor parameter should display Enabled while the Throttle Sweep Test is in progress. NOTE: Before replacing the throttle body assembly, make sure the throttle control circuits are not shorted to B+. If not the specified value, replace the throttle body assembly.
  6. 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.
  1. Ignition OFF, verify the following conditions do not exist with the throttle body assembly: A throttle blade that is not in the rest position A throttle blade that is binding open or closed A throttle blade that is free to move open or closed without spring pressure If a condition is found, replace the throttle body assembly.
  2. Ignition OFF, disconnect the harness connector at the throttle body assembly.
  3. Ignition ON, verify that a test lamp does not illuminate between each control circuit listed below and ground. TAC Motor Control Closed circuit terminal A TAC Motor Control Open circuit terminal B If test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition ON, verify that a test lamp does not illuminate between each control circuit listed below and B+. TAC Motor Control Closed circuit terminal A TAC Motor Control Open circuit terminal B If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  5. Ignition OFF, set the DMM to the 40 V scale, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms.
  6. Ignition OFF, measure the voltage using the DMM Min/Max Recording Mode function on each circuit listed below as the ignition is turned ON. The Max voltage should be within 1 V of B+. TAC Motor Control Closed circuit terminal A TAC Motor Control Open circuit terminal B If not within the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  7. If all circuits and connections test normal, replace the throttle body assembly.
  1. «Throttle Body Assembly Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «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

Repair Verification

  1. Install any components that have been removed or replaced during diagnosis.
  2. Perform any adjustments, programming or setup procedures that are required when a component is removed or replaced.
  3. Clear the DTCs with a scan tool.
  4. Turn OFF the ignition for 60 seconds.
  5. Perform the Throttle Sweep Test while observing the TAC Motor parameter with a scan tool. The TAC Motor parameter should display Enabled while the Throttle Sweep Test is in progress.
  6. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the «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) and perform the appropriate diagnostic procedure.
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundOpen/High ResistanceShort to Voltage
EC Ignition Relay Feedback Signal, Powertrain RelayP1682P1682P0690
Ignition 1 Signal, Ignition 1 Relay112
1. A short to ground or open/high resistance will cause a No Crank condition. 2. A short to voltage will cause the engine to continue to run with ignition OFF.
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, engine OFF, and ignition main and powertrain relay are commanded ON
Ignition 1 Signal, Ignition 1 Relay0 V0 V12 V
EC Ignition Relay Feedback Signal, Powertrain Relay0 V0 V12 V

Ignition Scan Tool Data

There are 2 ignition voltage circuits supplied to the engine control module (ECM). The first ignition circuit is provided by the powertrain relay, through a fuse. This ignition voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition voltage circuit is supplied by the ignition 1 relay through a fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition voltage circuits, DTC P1682 will set.

  1. The ignition is ON.
  2. System voltage is more than 7 V.
  3. The powertrain relay is commanded ON.
  4. DTC P1682 runs continuously when the above conditions are met.

The ECM detects that the voltage level difference is greater than 3 V between the 2 ignition 1 voltage circuits for less than 1 s.

DTC P1682 is a Type A DTC.

DTC P1682 is a Type A DTC.

This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test .

Schematic Reference

  1. «Engine Controls Schematics»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-wiring-schematic-diagrams)
  2. «Power Distribution Schematics»(/cadillac/cts/ii-2007-2014/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Electrical Center Identification Views»(/cadillac/cts/ii-2007-2014/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)
  4. «Probing Electrical Connectors»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__probing-electrical-connectors)
  5. «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)
  6. «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

Special Tools

J 35616-A/BT-8637 Connector Test Adapter Kit

  1. If DTCs P0685, P0689, or P0690 are set, diagnose those DTCs first.
  2. Ignition ON, engine OFF, observe both the Ignition 1 Voltage Signal and the EC Ignition Relay Feedback Signal parameters on the scan tool. There should be no more than 3 V difference between the 2 parameters.
  3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Note. You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition ON, observe the Ignition 1 Signal and the EC Ignition Relay Feedback scan tool parameter to determine which is more than 3 V lower than the other.
  2. Ignition OFF, remove the relay that corresponds to the scan tool parameter that is more than 3 V lower.
  3. Connect a 20 A fused jumper wire between B+ and the applicable ignition voltage circuit terminal 87 leading to the K20 ECM. Ignition ON, verify that the applicable scan tool parameter displays between 9-14 V. If the applicable scan tool parameter is less than the specified value, test the ignition voltage circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  4. Ignition OFF, connect a DMM set to the diode setting between the control circuit terminal 86 and ground. Verify the DMM displays OL. If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  5. Ignition ON, verify the DMM displays less than 1 V. If not the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  6. If all circuits test normal, replace the applicable relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Engine Control Module Programming and Setup (V8)»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__engine-control-module-programming-and-setup) for ECM replacement, setup, and programming
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
APP Sensor 1 SignalP2122P2138P2122P2123P2120, P2138
APP Sensor 1 5-Volt ReferenceP0335, P0651, P2122, P2138P2138P2122P2123, P2138, P0651P2120, P2138
APP Sensor 1 Low ReferenceP2138P2123P2120, P2138
APP Sensor 2 SignalP2127P2138P2127P2128P2120, P2138
APP Sensor 2 5-Volt ReferenceP0452, P0532, P0641, P2127, P2138P2138P2127P2128, P0641P2120, P2138
APP Sensor 2 Low ReferenceP2138P2128P2120, P2135
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: APP 1 varies 1.02-4.29 V
APP Sensor 1 Signal0 V0 V4.98 V
APP Sensor 1 5-Volt Reference0 V0 V4.98 V
APP Sensor 1 Low Reference5 V

APP Sensor 1

CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: APP 2 varies 0.50-2.50 V
APP Sensor 2 Signal0 V0 V4.98 V
APP Sensor 2 5-Volt Reference0 V0 V4.98 V
APP Sensor 2 Low Reference4.98 V

APP Sensor 2

The throttle actuator control (TAC) system uses two accelerator pedal position (APP) sensors to monitor the accelerator pedal position. The APP sensors 1 and 2 are located within the pedal assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit.

Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to pedal movement. The processors share and monitor data to verify that the indicated APP calculation is correct.

P2120, P2122, P2123, P2125, P2127, P2128

  1. DTC P0601, P0602, P0603, P0604, P0606, P060D, P062F, P0641, or P0651 are not set.
  2. The ignition is ON.
  3. The battery voltage is more than 6 volts.
  4. DTC P2120, P2122, P2123, P2125, P2127, P2128 run continuously when the above conditions are met.

P2138

  1. DTC P0601, P0602, P0603, P0604, P0606, P060D, P062F, P0641, P0651, P2120, P2122, P2123, P2125, P2127 or P2128 are not set.
  2. The ignition is ON.
  3. The battery voltage is more than 6 volts.
  4. DTC P2138 runs continuously when the above conditions are met.

P2120

The ECM detects that the APP sensor 1 voltage is less than 0.463 volts or more than 4.75 volts for less than 1 second.

P2122

The ECM detects that the APP sensor 1 voltage is less than 0.463 volts for less than 1 second.

P2123

The ECM detects that the APP sensor 1 voltage is more than 4.75 volts for less than 1 second.

P2125

The ECM detects that the APP sensor 2 voltage is less than 0.33 volts or more than 2.6 volts for less than 1 second.

P2127

The ECM detects that the APP sensor 2 voltage is less than or equal to 0.33 volt for less than 1 second.

P2128

The ECM detects that the APP sensor 2 voltage is more than 2.6 volts for less than 1 second.

The voltage difference between APP sensor 1 and APP sensor 2 exceeds a value of 8.07 percent with the pedal in the released position, or 10 percent with the pedal at wide open throttle (WOT) for less than 1 second.

  1. DTCs P2120, P2122, P2123, P2125, P2127, P2128, and P2138 are Type A DTCs.
  2. The control module commands the TAC system to operate in the Reduced Engine Power mode.
  3. A message center or an indicator displays Reduced Engine Power.
  4. Under certain conditions the control module commands the engine OFF.

DTCs P2120, P2122, P2123, P2125, P2127, P2128, and P2138 are Type A DTCs.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

  1. Ignition ON, observe the scan tool APP sensor 1 voltage parameter. The reading should be between 0.32-4.75 volts, and change with accelerator pedal input.
  2. Ignition ON, observe the scan tool APP sensors 2 voltage parameter. The reading should be between 0.32-4.75 volts and change with accelerator pedal input.
  3. Ignition ON, observe the scan tool APP sensors 1 and 2 parameter. The scan tool should indicate agree.
  4. Clear the DTCs with the scan tool. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records.
  5. Verify that DTC P2120 or P2125 are not the only throttle position DTCs set. If DTC P2120 or P2125 are the only DTCs set, replace the ECM.
  6. Verify that DTC P0641 or P0651 are not set. IF DTC P0641 or P0651 is set, refer to «DTC P0641 or P0651 (ECM)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-dtc-p0230-dtc-p0650) .
  7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  1. Ignition OFF, disconnect the harness connector at the accelerator pedal. Allow at least 60 seconds for the ECM to power down. This can be verified by a loss of communication message on the scan tool.
  2. Test for less than 5 ohms of resistance between each low reference circuit terminals A and D and ground. If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.8 volts between each 5-volt reference circuit terminals C and F and ground. If less than 4.8 volts, test the affected 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM. If greater than 5.2 volts, test the affected 5-volt reference circuit for short to voltage. If the circuit test normal, replace the ECM.
  4. Ignition ON, verify the scan tool APP sensor 1 and 2 voltages are less than 0.1 volt. If greater than 0.1 volt, test the APP sensor 1 and 2 signal circuits terminals B and E for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3A fused jumper wire between the signal circuit terminal E and the 5-volt reference circuit terminal F of the APP sensor 1. Verify the scan tool parameter APP sensor 1 voltage is greater than 4.8 volts. If less than 4.8 volts, test the APP sensor 1 signal circuit for an open or short to ground. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C of the APP sensor 2. Verify that the scan tool parameter APP sensor 2 voltage is greater than 4.8 volts. If less than 4.8 volts, test the APP sensor 2 signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
  7. Ignition OFF, disconnect the harness connector at the ECM.
  8. Test for less than 5 ohms of resistance on all APP sensor circuits between the following terminals: ECM X1 signal circuit terminal 47 to APP terminal E ECM X1 signal circuit terminal 49 to APP terminal B ECM X1 5-volt reference circuit terminal 35 to APP terminal C ECM X1 5-volt reference circuit terminal 33 to APP terminal F If greater than 5 ohms, repair the affected circuit for an open/high resistance.
  9. Test for infinite resistance between APP sensor 1 signal circuit terminal E and APP sensor 2 signal circuit terminal B. If less than infinite resistance, repair the short between APP sensor 1 signal circuit and APP sensor 2 signal circuits.
  10. If all circuits test normal, test the APP sensor. Refer to Component Testing for instructions. If the APP sensor tests normal, replace the ECM.

Component Test

Note. The Circuit/System Testing must be performed before proceeding with the Component Test.

Dynamic Test

  1. Install a 3A fused jumper wire between the 5-volt reference terminal of the applicable APP sensor and 5 volts. Install a jumper wire between the low reference terminal and a ground.
  2. Sweep the sensor through the entire range while monitoring the voltage between the signal terminal and the low reference terminal with a DMM. The voltage should vary between 0.30-4.98 volts without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the accelerator pedal assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accelerator Pedal Position Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-repair-instructions)
  2. «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
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
5V Reference CircuitP006D, P0641, P2228P006DP006D, P2228P006D, P0641, P2229P2227
BARO Sensor Signal CircuitP006D, P2228P006DP006D, P2228P006D, P2229P2227
Low Reference CircuitP006DP006D, P2229P2227
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The Ignition is ON Parameter Normal Range: BARO
5V Reference Circuit0 kPa0 kPa128 kPa
BARO Sensor Signal Circuit0 kPa1 kPa128 kPa
Low Reference Circuit128 kPa

BARO Sensor

The barometric pressure (BARO) sensor measures the pressure of the atmosphere. This pressure is affected by altitude and weather conditions. A diaphragm within the BARO sensor is displaced by the pressure changes that occur from varying altitudes and weather conditions. The sensor translates this diaphragm action into the voltage signal input that is used by the engine control module (ECM) for diagnostics, emissions control, and to calculate fuel delivery.

Changes in BARO due to weather are relatively small, while changes due to altitude are significant. Pressure can range from 56 kPa at an altitude of 4 267 meters (14,000 feet), to 104 kPa at or below sea level. The BARO sensor has a 5V reference circuit, a low reference circuit and a signal circuit. The BARO sensor provides a voltage signal to the ECM on a signal circuit relative to barometric pressure changes.

  1. DTCs P0068, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0220, P0502, P0503, P2135, P2228, P2229 are not set.
  2. The engine run time is greater than 10 seconds.

The ECM detects that 80 out of 100 consecutive BARO sensor samples vary greater than 10 kPa between each sample, for 10 seconds.

DTC P2227 is a Type B DTC.

DTC P2227 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

Special Tools

J 35555: Metal Mityvac

  1. Ignition ON, observe the scan tool MAP, SC Inlet Pressure, and BARO sensor parameters. The readings should be within 5 kPa of each other and also the current BARO for your location. 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) .
  2. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Engine running, monitor the BARO parameter with the scan tool for a steady value.

  1. If the BARO parameter is not a steady value, test the BARO circuit for an intermittent short or open. If all circuits test normal, replace the BARO sensor.

Note. You must perform the Circuit/System Testing before proceeding with the Component Test.

  1. Ignition ON, engine OFF, remove the BARO sensor.
  2. Install a 3A fused jumper wire between the 5V reference terminal 1 of the sensor and 5V reference.
  3. Install a jumper wire between the low reference terminal 2 of the sensor and ground.
  4. Install a jumper wire at the signal terminal 3 of the BARO sensor.
  5. Connect a DMM between the jumper wire from terminal 3 of the sensor and ground.
  6. Install the J 35555: Metal Mityvac to the BARO sensor vacuum port. Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 5.2-0V, without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the BARO sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Barometric Pressure Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «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
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
5V ReferenceP006D, P0641, P2228P006DP006D, P2228P006D, P0641 P2229P2227
BARO Sensor SignalP006D, P2228P006DP006D, P2228P006D, P2229P2227
Low ReferenceP006DP006D, P2229P2227
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON Parameter Normal Range : BARO
5V Reference0 kPa0 kPa128 kPa
BARO Sensor Signal0 kPa1 kPa128 kPa
Low Reference128 kPa

BARO Sensor

The barometric pressure (BARO) sensor has a 5V reference circuit, a low reference circuit, and a signal circuit. The engine control module (ECM) supplies 5V to the BARO sensor on a 5V reference circuit, and provides a ground on a low reference circuit. The BARO sensor provides a voltage signal to the ECM on a signal circuit relative to barometric pressure changes.

P2228-Key On Test

  1. DTCs P0120, P0121, P0122, P0123, P0220, P0222 or P0223 are not set.
  2. The ignition is ON.
  3. This DTC runs continuously when the above conditions are met.

P2228-Engine Running Test

  1. DTCs P0120, P0121, P0122, P0123, P0220, P0222 or P0223 are not set.
  2. The throttle position is greater than or equal to 0 percent and the engine speed is less than or equal to 800 RPM. OR The throttle position is greater than or equal to 12.5 percent and then engine speed is greater than 800 RPM.
  3. This DTC runs continuously when the above conditions are met.

P2229

  1. DTCs P0120, P0121, P0122, P0123, P0220, P0222, or P0223 are not set.
  2. The engine is running.
  3. The engine run time is greater than 4 minutes.
  4. The startup coolant temperature is between -30°C and +30°C (-22°F and +86°F).
  5. The throttle position is less than 1 percent.
  6. The engine speed is greater than 1,200 RPM.
  7. This DTC runs continuously when the above conditions are met.

P2228

The BARO is less than 50 kPa for less than 1 minute.

The BARO is greater than 115 kPa for less than 1 minute.

DTCs P2228 and P2229 are Type B DTCs.

DTCs P2228 and P2229 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Measuring Frequency»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__measuring-frequency)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 35555: Metal Mityvac

  1. Verify that the following DTCs are not set: P0641 or P0651. If any of the DTCs are set, refer to «DTC P0641 or P0651 (ECM)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-dtc-p0230-dtc-p0650) .
  2. Ignition ON, observe the BARO parameter with a scan tool. The BARO parameter should be within the range specified in the altitude vs. barometric pressure table. 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) .
  3. 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.
  1. Ignition OFF, disconnect the harness connector at the BARO sensor.
  2. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal 2 of the connector and a good ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2V between the 5V reference circuit terminal 1 and ground. If less than the specified range, test the 5V reference circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the ECM. If greater than the specified range, test the 5V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool BARO sensor parameter is less than 5 kPa. If greater than the specified range, tests the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5V reference circuit terminal 1. Verify the scan tool BARO sensor parameter is greater than 120 kPa. If less than the specified range, test the sensor signal circuit for an open/high resistance or a short to ground.
  6. If all circuits test normal, test or replace the BARO sensor.

Note. You must perform the Circuit/System Testing before proceeding with the Component Test.

  1. Ignition ON, engine OFF, remove the BARO sensor.
  2. Install a 3A fused jumper wire between the 5V reference terminal 1 of the sensor and 5V reference.
  3. Install a jumper wire between the low reference terminal 2 of the sensor and ground.
  4. Install a jumper wire at the signal terminal 3 of the BARO sensor.
  5. Connect a DMM between the jumper wire from terminal 3 of the sensor and ground.
  6. Install the J 35555: Metal Mityvac to the BARO sensor vacuum port. Slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 5.2-0V, without any spikes or dropouts. If the voltage is not within the specified range or is erratic, replace the BARO sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Barometric Pressure Sensor Replacement»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «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
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
HO2S SignalP0131, P0132, P0137, P0140, P0151, P0152, P0157, P0158, P1133P0131, P0132, P0133, P0134, P0137, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0157, P0160, P1133, P1153P0131, P0132, P0133, P0134, P0137, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0157, P0160, P1133, P1153P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160, P1133, P1153P0133, P0134, P013A, P013B, P013E, P013F, P0140, P0153, P0154, P0160, P1133, P1153, P2270, P2271
HO2S Low ReferenceP0131, P0132, P0133, P0134, P0138, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0158, P0160, P1133P0131, P0132, P0133, P0134, P0138, P013A, P013B, P013E, P013F, P0140, P0151, P0152, P0153, P0154, P0158, P0160, P1133, P1153P0134, P0138, P0140, P0154, P0158, P0160, P1133, P1153
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S Signal0 mVApproximately 470 mVApproximately 1,100 mV
HO2S Low Reference455 mVApproximately 450 mVApproximately 445 mV

HO2S Sensor 1 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.

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.

  1. DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.
  2. The ignition 1 voltage is between 10-18 volts.
  3. The engine run time is greater than 5 minutes.
  4. The engine speed is between 1,100-2,500 RPM.
  5. The mass air flow (MAF) is between 3-20 g/s.
  6. The vehicle speed is between 50-120 km/h (31-75 mph).
  7. The fuel level is greater than 10 percent.
  8. The fuel system is in Closed Loop.
  9. The catalytic converter temperature is between 550-900°C (1,022-1,652°F).
  10. The DTCs run once per ignition cycle when the above conditions are met.

P2270

The ECM does not detect a HO2S voltage greater than 805 mV before accumulated mass air flow exceeds 550 grams.

P2272

The ECM does not detect a HO2S voltage greater than 775 mV before the accumulated mass air flow exceeds 82 grams.

DTCs P2270 and P2272 are Type B DTCs.

DTCs P2270 and P2272 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «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

  1. Ignition ON, observe the DTC information with a scan tool. Verify that no B52 HO2S heater DTCs are set. If any B52 HO2S heater DTCs are set, perform those diagnostics first. 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) .
  2. Engine idling, move the appropriate B52 HO2S 2 harness connector and the engine control module (ECM) harness connector while monitoring the B52 HO2S 2 voltage parameter with a scan tool. Verify that the B52 HO2S parameter does not change abruptly while moving the related harnesses. If the B52 HO2S parameter does change abruptly while moving the related harnesses repair the circuit as necessary.
  3. Engine idling at operating temperature, observe the appropriate B52 HO2S 2 parameter with a scan tool. Verify the following: The B52 HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes. The B52 HO2S 2 should fluctuate at less than 380 mV or greater than 520 mV. The values should not remain within 380 mV and 520 mV.
  4. 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.

Note. All modules must be powered down or misdiagnosis may result.

  1. Ignition OFF, disconnect the harness connector at the appropriate B52 HO2S.
  2. 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. If the circuit tests normal, replace the ECM.
  3. Ignition ON, verify the appropriate scan tool B52 HO2S parameter is approximately 450 mV. If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool HO2S parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
  5. Verify none of the following conditions exist: Lean fuel injectors-Refer to «Fuel Injector Diagnosis (w/J39021 or w/Tech 2)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Diagnosis (w/CH47976)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Water intrusion in the B52 HO2S harness connector Low fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Exhaust leaks near the B52 HO2S Engine vacuum leaks Contaminated B52 HO2S - Silicon An engine mechanical condition- «Symptoms - Engine Mechanical»(/cadillac/cts/ii-2007-2014/remont/mechanical/#engine-mechanical-62l-diagnostic-information-and-procedures) If you find any of the above conditions, repair as necessary.
  6. If all circuits test normal, replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  3. «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
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
HO2S High SignalP0131, P0132, P0137, P0140, P0151, P0152, P0157, P0158, P1133P0131, P0132, P0133, P0134, P0137, P013C, P013D, P0140, P014A, P014B, P0151, P0152, P0153, P0154, P0157, P0160, P1133, P1153P0131, P0132, P0133, P0134, P0137, P013C, P013D, P0140, P014A, P014B, P0151, P0152, P0153, P0154, P0157, P0160, P1133, P1153P0132, P0134, P0138, P0140, P0152, P0154, P0158, P0160, P1133, P1153P0133, P0134, P013C, P013D, P0140, P014A, P014B, P0153, P0154, P0160, P1133, P1153, P2272, P2273
HO2S Low SignalP0131, P0132, P0133, P0134, P0138, P013C, P013D, P0140, P014A, P014B, P0151, P0152, P0153, P0154, P0158, P0160, P1133P0131, P0132, P0133, P0134, P0138, P013C, P013D, P0140, P014A, P014B, P0151, P0152, P0153, P0154, P0158, P0160, P1133, P1153P0134, P0138, P0140, P0154, P0158, P0160, P1133, P1153
CircuitShort to GroundOpenShort to Voltage
Parameter Normal Range: 200-800 mV
HO2S High Signal0 mVApproximately 470 mVApproximately 1,100 mV
HO2S Low Signal455 mVApproximately 450 mVApproximately 445 mV

HO2S Sensor 1 Voltage

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The control module supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the control module operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream.

  1. Before the ECM can report DTC P2271, or P2273 failed, DTCs P013A, P013C, P013E, P014A, P2270, and P2272 must run and pass.
  2. DTCs P0036, P0037, P0038, P0137, P0138, P0140, P0141, P0443, P0458, P0459, P2232 are not set.
  3. The ignition 1 voltage is between 10-18 volts.
  4. The engine speed is between 500-5,000 RPM.
  5. The mass air flow (MAF) is between 3-50 g/s.
  6. The vehicle speed is between 24-132 km/h (15-82 mph).
  7. The fuel level is greater than 10 percent.
  8. The fuel system is in Closed Loop.
  9. The engine run time is equal to or more than 5 minutes.
  10. The accelerator pedal position (APP) is steady.
  11. The torque converter clutch is TCC is applied.
  12. The DTCs run once per ignition cycle, during decel fuel cut-off, when the above conditions are met.

P2271

The ECM does not detect an HO2S voltage less than 150 mV before accumulated mass air flow exceeds 550 grams.

P2273

The ECM does not detect an HO2S voltage less than 100 mV before the accumulated mass air flow exceeds 76 grams.

DTCs P2271 or P2273 are Type B DTCs.

DTCs P2271 or P2273 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «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

  1. Ignition ON, observe the DTC information with a scan tool. Verify that no B52 HO2S heater DTCs are set. If any B52 HO2S heater DTCs are set, perform those diagnostics first. 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) .
  2. Engine idling, move the appropriate B52 HO2S 2 harness connector and the engine control module (ECM) harness connector while monitoring the B52 HO2S 2 voltage parameter with a scan tool. Verify that the B52 HO2S parameter does not change abruptly while moving the related harnesses. If the B52 HO2S parameter does change abruptly while moving the related harnesses repair the circuit as necessary.
  3. Engine idling at operating temperature, observe the appropriate B52 HO2S 2 parameter with a scan tool. Verify the following: The B52 HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes. The B52 HO2S 2 should fluctuate at less than 380 mV or greater than 520 mV. The values should not remain within 380 mV and 520 mV.
  4. 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.

Note. All modules must be powered down or misdiagnosis may result.

  1. Ignition OFF, disconnect the harness connector at the appropriate B52 HO2S.
  2. 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. If the circuit tests normal, replace the ECM.
  3. Ignition ON, verify the appropriate scan tool B52 HO2S parameter is approximately 450 mV. If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 ECM. If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool B52 HO2S parameter is less than 60 mV. If greater than the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the K20 ECM.
  5. Verify none of the following conditions exist: Rich fuel injectors-Refer to «Fuel Injector Diagnosis (w/J39021 or w/Tech 2)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Fuel Injector Diagnosis (w/CH47976)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Water intrusion in the B52 HO2S harness connector High fuel system pressure-Refer to «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool)»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-symptom-troubleshooting-and-diagnosis) Fuel saturation of the evaporative emission (EVAP) canister If you find any of the above conditions, repair as necessary.
  6. If all circuits test normal, replace the appropriate B52 HO2S.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  3. «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
  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
IGN VoltageP2534P2534

The fuel pump control module monitors the ignition voltage circuit in order to determine if the voltage is within the normal operating range.

The engine is running.

The FPCM detects that the IGN voltage is less than 6.0 V.

DTC P2534 is a Type A DTC.

DTC P2534 is a Type A DTC.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

  1. Verify that DTC P0562 is not set. If DTC P0562 is set, refer to «DTC P0562»(/cadillac/cts/ii-2007-2014/remont/charging-system/#battery-charging-system-and-starting-system) .
  2. Ignition OFF, disconnect the harness connector of the K27 fuel pump control module.
  3. Ignition ON, test for greater than 11 V between the IGN voltage circuit terminal 15 and ground. If less than the specified voltage, test the IGN voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ECM/TCM fuse is open, test the voltage circuit for a short to ground. If the circuit tests normal, test or replace the Run/Crank relay.
  4. If all circuits test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «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
  1. 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.
  2. 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.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

To improve shift feel, the transmission control module (TCM) may request that the engine control module (ECM) reduce engine torque during shift events. When such a request is received, the ECM responds by retarding the base ignition timing and notifying the TCM that the request has succeeded. If the ECM is unable to comply with the request, the ECM sends the TCM a message that the request has failed.

The torque reduction request is sent to the ECM through a communication network called the controller area network (CAN). Two circuits are used to communicate CAN data between the ECM and TCM. A fault in the CAN will not cause DTC P2544 to set by itself. If a CAN fault occurs, other DTCs will set before DTC P2544.

When the TCM receives a torque reduction failure message from the ECM, then DTC P2544 will set. DTC P2544 is a type B DTC.

  1. The engine run time is greater than 5 seconds.
  2. No other CAN errors are present.

The ECM notifies the TCM that a torque reduction request has failed for 2 seconds.

  1. DTC P2544 is a Type B DTC.
  2. The TCM commands maximum line pressure.
  3. The TCM freezes transmission adaptive functions.
  4. At the time of the first failure, the TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as a Failure Record.
  5. At the time of the second failure, the ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as a Freeze Frame.
  6. The TCM stores DTC P2544 in TCM history.
  1. DTC P2544 is a Type B DTC.
  2. The ECM turns OFF the MIL after the sixth consecutive drive trip in which the TCM does not send a MIL illumination request.
  3. A scan tool can clear the DTC.
  4. The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non emission related diagnostic fault occurring.
  5. The TCM cancels the DTC default actions when the ignition is OFF long enough in order to power down the TCM.

This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test

DTC Type Reference

Observe the DTCs in the scan tool

  1. If DTC P0604 is set, replace the ECM.
  2. If DTC P0604 is not set, replace the TCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM or TCM replacement, programming, and setup.

  1. 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.
  2. 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.
  3. «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.
CircuitShort to GroundOpen or High ResistanceShort to VoltageSignal Performance
Fuel Pump High ControlP0231P023FP0232P023F, P2635
Fuel Pump Low ControlP023FP023F, P2635

The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received, the fuel pump control module closes the ground switch of the fuel pump and also supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.

  1. DTC P018B, P018C, P018D, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active.
  2. DTC P0641 has not failed this ignition cycle.
  3. Fuel pump control is enabled and the fuel pump control state is normal.
  4. The system voltage is greater than 11 V.
  5. The engine has been running for more than 30 seconds.

This DTC sets when the fuel pump control module detects a predetermined fuel pressure performance degradation between the desired fuel rail pressure and the current estimated fuel rail pressure.

DTC P2635 is a Type B DTC.

DTC P2635 is a Type B DTC.

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

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «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)
  4. «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

  1. Verify that DTCs P018C, P018D, P0231, P0232, or P023F are not set. If the 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) .
  2. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
  3. Ignition ON, test for less than 5.0 ohms between the G12 fuel pump low reference circuit terminal 2 and ground. If greater than the specified range, test the G12 fuel pump low reference circuit for a high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  4. Ignition OFF, install a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
  5. Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K27 fuel pump control module.
  6. Perform the «Fuel System Diagnosis»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-30l-or-36l-symptom-troubleshooting-and-diagnosis) to verify proper fuel pressure. If the fuel pressure is not normal, replace the G12 fuel pump
  7. If all circuits test normal, replace the K27 fuel pump control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Tank Fuel Pump Module Replacement - Right Side»(/cadillac/cts/ii-2007-2014/remont/testing-diagnostics/#engine-controls-and-fuel-62l-repair-instructions)
  2. «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

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• Power Distribution Schematics
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Electrical Center Identification Views
• Probing Electrical Connectors
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Relay Replacement (Attached to Wire Harness)
• Diagnostic Trouble Code (DTC) List - Vehicle
• Troubleshooting with a Test Lamp
• DTC P0106
• Symptoms - Engine Exhaust
• Fuel Injector Diagnosis (w/J39021 or w/Tech 2)
• Symptoms - Engine Mechanical
• Fuel System Description
• DTC P0231, P0232, or P023F
• Symptoms - Antilock Brake System
• Engine Control Module Description
• Crankcase Ventilation System Inspection/Diagnosis
• Throttle Actuator Control (TAC) System Description
• Throttle Body Assembly Replacement
• Battery Inspection/Test
• Engine Control Module Programming and Setup (V8)
• DTC P0641 or P0651 (ECM)
• Accelerator Pedal Position Sensor Replacement
• Altitude Versus Barometric Pressure
• Measuring Frequency
• Heated Oxygen Sensor Resistance Learn Reset Caution
• Fuel System Diagnosis
• Diagnostic Aids

More articles — Engine Performance