Engine Mechanical - 2.0l (Ltg) or 2.5l (Lcv) - Diagnostic Information and Procedures Cadillac ATS I

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The four state switchable engine mount (also known as vacuum switchable engine mounts) provides the ability to change the stiffness of the engine mount as a means to reduce engine vibrations felt by the driver. The four state switchable engine mount characteristics are controlled by applying vacuum or atmospheric pressure to the bounce and idle ports of the mount; vacuum is supplied to the mount by activating a solenoid. Applying different combinations of vacuum or atmospheric pressure determines the mount stiffness. The commanded state of the mount is dependent on various vehicle operating conditions, such as engine speed, transmission gear, and vehicle speed. The engine mount solenoid valves control the switchable engine mounts by providing vacuum when desired. The engine mount solenoid valves are provided battery voltage. The fuel pump control module provides ground to activate the engine mount solenoid valves.

Conditions for Running the DTC

Engine Running

Conditions for Setting the DTC

Short to voltage for more than 1.2 seconds.

Action Taken When the DTC Sets

The fuel pump control module will not activate the switchable engine mounts.

Conditions for Clearing the DTC

The condition for the DTC is no longer present. The fuel pump control module clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles

Diagnostic Aid

A problem with the engine mount solenoid valve vacuum supply system may cause the engine mount solenoid valves to stop working without setting any DTCs. Diagnose all vacuum supply system concerns before performing the Circuit/System Testing procedure below.

Reference Information

Schematic Reference

Engine Mechanical Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Vacuum Operated Engine Mounts Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify the Q80R Engine Mount Solenoid Valve-Right turns on and off or clicks when commanding the Driveline Mount Output 1 On and Off with a scan tool. If the Q80R Engine Mount Solenoid Valve-Right does not turn on and off or click Refer to Circuit/System Testing If the Q80R Engine Mount Solenoid Valve-Right turns on and off or clicks
3. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the Q80R Engine Mount Solenoid Valve-Right, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. Refer to «Power Mode Mismatch»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the Q80R Engine Mount Solenoid Valve-Right. If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 1 and the ignition circuit terminal 2.
4. Verify the test lamp turns ON and OFF when commanding the Driveline Mount Output 1 On and Off with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Fuel Pump Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K27 Fuel Pump Control Module. If the test lamp is always ON Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Fuel Pump Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K27 Fuel Pump Control Module. If the test lamp turns ON and OFF
5. Test or replace the Q80R Engine Mount Solenoid Valve-Right.

Component Testing

Dynamic Test

1. Disconnect the harness connector at the Q80R Engine Mount Solenoid Valve-Right.
2. Install a 10A fused jumper wire between the B+ terminal 2 and 12 V. Install a jumper wire between the control terminal 1 and ground.
3. Verify the Q80R Engine Mount Solenoid Valve-Right turns on and off or clicks. If the Q80R Engine Mount Solenoid Valve-Right does not turn on and off or click. Replace the Q80R Engine Mount Solenoid Valve-Right. If the Q80R Engine Mount Solenoid Valve-Right does turn on and off or clicks.
4. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

1. «Engine Mount Vacuum Valve Replacement»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-on-vehicle) for engine mount solenoid valve replacement.
2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The four state switchable engine mount (also known as vacuum switchable engine mounts) provides the ability to change the stiffness of the engine mount as a means to reduce engine vibrations felt by the driver. The four state switchable engine mount characteristics are controlled by applying vacuum or atmospheric pressure to the bounce and idle ports of the mount; vacuum is supplied to the mount by activating a solenoid. Applying different combinations of vacuum or atmospheric pressure determines the mount stiffness. The commanded state of the mount is dependent on various vehicle operating conditions, such as engine speed, transmission gear, and vehicle speed. The engine mount solenoid valves control the switchable engine mounts by providing vacuum when desired. The engine mount solenoid valves are provided battery voltage. The fuel pump control module provides ground to activate the engine mount solenoid valves.

Engine Running

Short to voltage for more than 1.2 seconds.

The fuel pump control module will not activate the switchable engine mounts.

The condition for the DTC is no longer present. The fuel pump control module clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles

A problem with the engine mount solenoid valve vacuum supply system may cause the engine mount solenoid valves to stop working without setting any DTCs. Diagnose all vacuum supply system concerns before performing the Circuit/System Testing procedure below.

Schematic Reference

Engine Mechanical Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Vacuum Operated Engine Mounts Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify the Q80L Engine Mount Solenoid Valve-Left turns on and off or clicks when commanding the Driveline Mount Output 2 On and Off with a scan tool. If the Q80L Engine Mount Solenoid Valve-Left does not turn on and off or click Refer to Circuit/System Testing If the Q80L Engine Mount Solenoid Valve-Left does turn on and off or clicks
3. All OK.

1. Ignition OFF, disconnect the harness connector at the Q80L Engine Mount Solenoid Valve-Left, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. Refer to «Power Mode Mismatch»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the Q80L Engine Mount Solenoid Valve-Left. If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 1 and the ignition circuit terminal 2.
4. Verify the test lamp turns ON and OFF when commanding the Driveline Mount Output 1 On and Off with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Fuel Pump Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K27 Fuel Pump Control Module. If the test lamp is always ON Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Fuel Pump Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K27 Fuel Pump Control Module. If the test lamp turns ON and OFF
5. Test or replace the Q80L Engine Mount Solenoid Valve-Left.

Dynamic Test

1. Disconnect the harness connector at the Q80L Engine Mount Solenoid Valve-Left.
2. Install a 10A fused jumper wire between the B+ terminal 2 and 12 V. Install a jumper wire between the control terminal 1 and ground.
3. Verify the Q80L Engine Mount Solenoid Valve-Left turns on and off or clicks. If the Q80L Engine Mount Solenoid Valve-Left does not turn on and off or click. Replace the Q80L Engine Mount Solenoid Valve-Left. If the Q80L Engine Mount Solenoid Valve-Left does turn on and off or clicks.
4. All OK

Perform the Diagnostic Repair Verification after completing the repair.

1. «Engine Mount Vacuum Valve Replacement»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-on-vehicle) for engine mount solenoid valve replacement.
2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming, and setup.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine oil pressure control solenoid is a two port solenoid valve used to control engine oil pressure inside the mechanical engine oil pump. The ECM controls the commanded states of the engine oil pressure control solenoid with the following ECM inputs.

1. Engine Speed
2. Engine Oil Temperature (calculated from the Engine Coolant Temperature Sensor)
3. Engine Oil Pressure
4. Engine Run Time

With the engine oil pressure control solenoid commanded Off, engine oil pressure is higher. When commanded On engine oil pressure is lower. The purpose of this diagnostic is to isolate an electrical problem with the engine oil pressure control solenoid or wiring.

1. The system voltage is greater than 11 V.
2. Engine running
3. DTC P06DA, P06DB or P06DC 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 a minimum of 0.25 s.

1. DTC P06DB is a Type A DTC.
2. DTC P06DA and P06DC are Type B DTCs.
3. ECM commands the engine oil pressure control solenoid valve OFF.
4. ECM commands Reduced Engine Power.

Conditions for Clearing the MIL/DTC

1. DTC P06DB is a Type A DTC.
2. DTC P06DA and P06DC are Type B DTCs.

Schematic Reference

Engine Mechanical Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify the parameters listed below do not display Malfunction when commanding the Engine Oil Pressure Control Solenoid Valve ON and OFF with a scan tool. Engine Oil Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status Engine Oil Pressure Control Solenoid Valve Control Circuit Open Test Status Engine Oil Pressure Control Solenoid Valve Control Circuit High Voltage Test Status If Malfunction is displayed Refer to Circuit/System Testing. If Malfunction is not displayed
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.
4. Verify the DTC does not set. If any DTC sets Refer to Circuit/System Testing. If the DTC does not set
5. All OK.

1. Ignition OFF, disconnect the harness connector at the Q44 Engine Oil Pressure Control Solenoid Valve, ignition ON.
2. Verify that a test lamp illuminates between the ignition circuit terminal 1 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. NOTE: An internal short in any component supplied by the fuse may cause the fuse to open and set a DTC when the component is activated. Test for infinite resistance between the ignition circuit and ground If less than infinite resistance, repair the short to ground in the circuit. If infinite resistance, test all the components connected to fuse and replace as necessary. If the test lamp illuminates
3. Verify that a test lamp does not illuminate between the ignition circuit terminal 1 and the control circuit terminal 2. If the test lamp illuminates Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If the test lamp does not illuminate
4. Remove the test lamp, command the Q44 Engine Oil Pressure Control Solenoid Valve ON with a scan tool.
5. Verify the scan tool Engine Oil Pressure Control Solenoid Valve Control Circuit High Voltage Test Status parameter displays OK. If OK is not displayed Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 Engine Control Module. If OK is displayed
6. Install a 3 A fused jumper wire between the control circuit terminal 2 and the ignition circuit terminal 1.
7. Verify the scan tool Engine Oil Pressure Control Solenoid Valve Circuit High Voltage Test Status parameter is displaying Malfunction when commanding the Engine Oil Pressure Control Solenoid Valve ON with a scan tool. If Malfunction is not displayed Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms replace the K20 Engine Control Module. If Malfunction is displayed
8. Test or replace the Q44 Engine Oil Pressure Control Solenoid Valve.

Static Test

1. Ignition OFF, disconnect the harness connector at the Q44 Engine Oil Pressure Control Solenoid Valve.
2. Test for 10-30 ohms between the control terminal 2 and the ignition voltage terminal 1. If not between 10.0-30.0 ohms Replace the Q44 Engine Oil Pressure Control Solenoid Valve. If between 10.0-30.0 ohms
3. Test for infinite resistance between each terminal and the Q44 Engine Oil Pressure Control Solenoid Valve housing. If not OL Replace the Q44 Engine Oil Pressure Control Solenoid Valve. If OL
4. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Oil Pump Flow Control Valve Replacement»(/cadillac/ats/i-2012-2014/remont/testing-diagnostics/#engine-controlsfuel-20l-ltg-or-25l-lcv-repair-instructions) Engine Oil Pressure Control Solenoid Valve Replacement
2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine oil pressure control solenoid is a two port solenoid valve used to control engine oil pressure inside the mechanical engine oil pump. The ECM controls the commanded states of the engine oil pressure control solenoid with the following ECM input's.

1. Engine Speed
2. Engine Oil Temperature (calculated from the Engine Coolant Temperature Sensor)
3. Engine Oil Pressure
4. Engine Run Time

With the engine oil pressure control solenoid commanded Off, engine oil pressure is higher. When commanded On engine oil pressure is lower. The purpose of this diagnostic is to isolate either a stuck on or stuck off engine oil pressure control solenoid.

P06DD

1. DTC P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0128, P0335, P0336, P0521, P0522, P0523, P06DA, P06DB, P06DC, P06DD, P06DE, P111E, P2227, P2228, P2229 or P2230 is not set.
2. Engine speed within range of 1,500 RPM to 2,500 RPM.

P06DE

1. DTC P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0117, P0118, P0119, P0128, P0335, P0336, P0521, P0522, P0523, P06DA, P06DB, P06DC, P06DD, P06DE, P111E, P2227, P2228, P2229 or P2230 is not set.
2. Engine running for greater than 20 s.
3. Engine speed is within range of 1500 RPM to 2500 RPM.
4. Engine oil pressure control solenoid in low pressure for greater than 1.5 s.

P06DD or P06DE

Engine oil pressure is above or below a calibrated amount during the time the solenoid is changing from ON to OFF states.

P06DD

DTC P06DD is a Type B DTC.

P06DE

DTC P06DE is a Type A DTC.

P06DD

DTC P06DD is a Type B DTC.

P06DE

DTC P06DE is a Type A DTC.

Schematic Reference

Engine Mechanical Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Verify correct engine oil level and condition. Refer to «Engine Mechanical Specifications (LCV)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-specifications__engine-mechanical-specifications-lcv) , «Engine Mechanical Specifications (LTG)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-specifications__engine-mechanical-specifications-ltg) .
2. Engine Running, increase and maintain the engine speed at 1,800 RPM.
3. Verify the scan tool Engine Oil Pressure parameter changes greater than 30 kPa (4 PSI) when commanding the Engine Oil Pressure Control Solenoid On and Off. If the parameter does not change Replace the Q44 Engine Oil Pressure Control Solenoid. If the parameter changes
4. 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.
5. Verify the DTC does not set. If the DTC sets Refer to «Oil Pressure Diagnosis and Testing»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-pressure-diagnosis-and-testing) . If the DTC does not set
6. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

Oil Pump Flow Control Valve Replacement Engine Oil Pressure Control Solenoid Replacement

Strategy Based Diagnostics

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables, if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views (LCV)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-component-locator) , «Engine Component Description (LCV)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-description-and-operation) , and «Lubrication Description»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-description-and-operation) .

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system condition. The diagnostic flow is the place to start when repairs are necessary.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the engine.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Check for the correct oil level, proper oil viscosity, and correct filter application.
4. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
5. Compare the engine sounds, if applicable, to a known good engine and make sure you are not trying to correct a normal condition.

Intermittent

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Base Engine Misfire without Internal Engine Noises»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-without-internal-engine)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-internal)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-valve)
4. «Base Engine Misfire with Coolant Consumption»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-coolant-consumption)
5. «Base Engine Misfire with Excessive Oil Consumption»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-excessive-oil)
6. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-noise-on-start-up-but-only)
7. «Upper Engine Noise, Regardless of Engine Speed»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__upper-engine-noise-regardless-of-engine)
8. «Lower Engine Noise, Regardless of Engine Speed»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__lower-engine-noise-regardless-of-engine)
9. «Engine Noise Under Load»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-noise-under-load)
10. «Engine Will Not Crank - Crankshaft Will Not Rotate»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft)
11. «Engine Compression Test»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-compression-test)
12. «Oil Consumption Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-consumption-diagnosis)
13. «Oil Pressure Diagnosis and Testing»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-pressure-diagnosis-and-testing)
14. «Oil Leak Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-leak-diagnosis)
15. «Drive Belt Chirping, Squeal, and Whine Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
16. «Drive Belt Rumbling and Vibration Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
17. «Drive Belt Falls Off and Excessive Wear Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
18. «Drive Belt Tensioner Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables, if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views (LTG)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-component-locator) , «Engine Component Description (LTG)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-description-and-operation) and «Lubrication Description»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-description-and-operation) .

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system condition. The diagnostic flow is the place to start when repairs are necessary.

1. Inspect for aftermarket devices which could affect the operation of the engine.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Check for the correct oil level, proper oil viscosity, and correct filter application.
4. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
5. Compare the engine sounds, if applicable, to a known good engine and make sure you are not trying to correct a normal condition.

Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Base Engine Misfire without Internal Engine Noises»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-without-internal-engine)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-internal)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-abnormal-valve)
4. «Base Engine Misfire with Coolant Consumption»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-coolant-consumption)
5. «Base Engine Misfire with Excessive Oil Consumption»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__base-engine-misfire-with-excessive-oil)
6. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-noise-on-start-up-but-only)
7. «Upper Engine Noise, Regardless of Engine Speed»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__upper-engine-noise-regardless-of-engine)
8. «Lower Engine Noise, Regardless of Engine Speed»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__lower-engine-noise-regardless-of-engine)
9. «Engine Noise Under Load»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-noise-under-load)
10. «Engine Will Not Crank - Crankshaft Will Not Rotate»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-will-not-crank-crankshaft)
11. «Engine Compression Test»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__engine-compression-test)
12. «Turbocharger Leaking Fluids Externally»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__turbocharger-leaking-fluids-externally)
13. «Turbocharger Noise»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__turbocharger-noise)
14. «Turbocharger Smoke or Smell»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__turbocharger-smoke-or-smell)
15. «Turbocharger Loss of Boost Pressure»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__turbocharger-loss-of-boost-pressure)
16. «Oil Consumption Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-consumption-diagnosis)
17. «Oil Pressure Diagnosis and Testing»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-pressure-diagnosis-and-testing)
18. «Oil Leak Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__oil-leak-diagnosis)
19. «Drive Belt Chirping, Squeal, and Whine Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
20. «Drive Belt Rumbling and Vibration Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
21. «Drive Belt Falls Off and Excessive Wear Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures)
22. «Drive Belt Tensioner Diagnosis»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-diagnostic-information-and-procedures__drive-belt-tensioner-diagnosis)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The four state switchable engine mount (also known as vacuum switchable engine mounts) provides the ability to change the stiffness of the engine mount as a means to reduce engine vibrations felt by the driver. The four state switchable engine mount characteristics are controlled by applying vacuum or atmospheric pressure to the bounce and idle ports of the mount; vacuum is supplied to the mount by activating a solenoid. Applying different combinations of vacuum or atmospheric pressure determines the mount stiffness. The commanded state of the mount is dependent on various vehicle operating conditions, such as engine speed, transmission gear, and vehicle speed. The engine mount solenoid valves control the switchable engine mounts by providing vacuum when desired. The engine mount solenoid valves are provided battery voltage. The fuel pump control module provides ground to activate the engine mount solenoid valves.

A problem with the engine mount solenoid valve vacuum supply system may cause the engine mount solenoid valves to stop working without setting any DTCs. Diagnose all vacuum supply system concerns before performing the Circuit/System Testing procedure below.

Schematic Reference

Engine Mechanical Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Vacuum Operated Engine Mounts Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON.
2. Verify the Engine Mount Solenoid Valves turn on and off or click when commanding the Driveline Mount Output 1 and 2 On and Off with a scan tool. If the Engine Mount Solenoid Valves does not turn on and off or click Refer to Circuit/System Testing If the Engine Mount Solenoid Valves turn on and off or click
3. All OK.

1. Ignition OFF, disconnect the appropriate Engine Mount Solenoid Valve harness connector, ignition ON.
2. Verify a test lamp illuminates between the ignition circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF, remove the test lamp. Test for less than 2 ohms in the ignition circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. Refer to «Power Mode Mismatch»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures) . If the test lamp does not illuminate and the circuit fuse is open Ignition OFF, remove the test lamp. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the appropriate Engine Mount Solenoid Valve. If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 1 and the ignition circuit terminal 2.
4. Verify the test lamp turns ON and OFF when commanding the Driveline Mount Output 1 and 2 On and Off with a scan tool. If the test lamp is always OFF Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Pump Control Module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K27 Fuel Pump Control Module. If the test lamp is always ON Ignition OFF, remove the test lamp, disconnect the harness connector at the K27 Fuel Pump Control Module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K27 Fuel Pump Control Module. If the test lamp turns ON and OFF
5. Test or replace the appropriate Engine Mount Solenoid Valve.

Dynamic Test

1. Disconnect the harness connector at the appropriate Engine Mount Solenoid Valve.
2. Install a 10A fused jumper wire between the B+ terminal 2 and 12 V. Install a jumper wire between the control terminal 1 and ground.
3. Verify the appropriate Engine Mount Solenoid Valve turns on and off or clicks. If the Engine Mount Solenoid Valve does not turn on and off or click. Replace the appropriate Engine Mount Solenoid Valve. If the Engine Mount Solenoid Valve does turn on and off or click.
4. All OK

Perform the Diagnostic Repair Verification after completing the repair.

1. «Engine Mount Vacuum Valve Replacement»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-on-vehicle) for engine mount solenoid valve replacement.
2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for fuel pump control module replacement, programming, and setup.

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire without Internal Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Internal Lower Engine Noises

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire with Abnormal Valve Train Noise

Base Engine Misfire with Coolant Consumption

Base Engine Misfire with Coolant Consumption

Base Engine Misfire with Excessive Oil Consumption

Base Engine Misfire with Excessive Oil Consumption

Engine Noise on Start-Up, but Only Lasting a Few Seconds

Engine Noise on Start-Up, but Only Lasting a Few Seconds

Upper Engine Noise, Regardless of Engine Speed

Upper Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Lower Engine Noise, Regardless of Engine Speed

Engine Noise Under Load

Engine Noise Under Load

Engine Will Not Crank - Crankshaft Will Not Rotate

Engine Will Not Crank - Crankshaft Will Not Rotate

Coolant in Combustion Chamber

Coolant in Combustion Chamber

Coolant in Engine Oil

Coolant in Engine Oil

Engine Compression Test

1. Charge the battery if the battery is not fully charged.
2. Disable the ignition system.
3. Disable the fuel injection system.
4. Remove all spark plugs.
5. Turn the ignition to the ON position.
6. Depress the accelerator pedal to position the throttle plate wide open.
7. Start with the compression gauge at zero and crank the engine through 4 compression strokes, 4 puffs.
8. Measure the compression for each cylinder. Record the readings.
9. If a cylinder has low compression, inject approximately 15 ml (1 tablespoon) of engine oil into the combustion chamber through the spark plug hole. Measure the compression again and record the reading.
10. The minimum compression in any 1 cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 690 kPa (100 psi). For example, if the highest pressure in any 1 cylinder is 1 035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). (1 035 x 70% = 725) (150 x 70% = 105). Normal - Compression builds up quickly and evenly to the specified compression for each cylinder. Piston Rings Leaking - Compression is low on the first stroke. Compression builds up with the following strokes, but does not reach normal. Compression improves considerably when you add oil. Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does not improve much when you add oil. If 2 adjacent cylinders have lower than normal compression, and injecting oil into the cylinders does not increase the compression, the cause may be a head gasket leaking between the cylinders.

Turbocharger Leaking Fluids Externally

Turbocharger Leaking Fluids Externally

Turbocharger Noise

Some noise is normal. Compare to a known good vehicle.

Turbocharger Noise

Turbocharger Smoke or Smell

Turbocharger Smoke or Smell

Turbocharger Loss of Boost Pressure

Turbocharger Loss of Boost Pressure

Cylinder Leakage Test

Special Tools

EN 35667-A Cylinder Head Leakdown Tester

For equivalent regional tools, refer to Special Tools .

Note. A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High leakage may indicate one or more of the following

1. Worn or burnt valves
2. Broken valve springs
3. Stuck valve lash adjusters
4. Incorrect valve lash/adjustment
5. Damaged piston
6. Worn piston rings
7. Worn or scored cylinder bore
8. Damaged cylinder head gasket
9. Cracked or damaged cylinder head
10. Cracked or damaged engine block

1. Disconnect the battery ground negative cable.
2. Remove the spark plugs. Refer to «Spark Plug Replacement»(/cadillac/ats/i-2012-2014/remont/testing-diagnostics/#engine-controlsfuel-20l-ltg-or-25l-lcv-repair-instructions) in Engine Controls.
3. Rotate the crankshaft to place the piston in the cylinder being tested at Top Dead Center (TDC) of the compression stroke.
4. Install the EN 35667-A tester or equivalent.
5. Apply shop air pressure to the EN 35667-A tester and adjust according to the manufacturers instructions.
6. Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions: Air leakage sounds at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage sounds at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
7. Perform the leakage test on the remaining cylinders and record the values.

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/ats/i-2012-2014/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/ats/i-2012-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Typical Scan Tool Data

Engine Oil Level Switch

The engine oil level sensor/switch is normally-closed with proper engine oil level. The switch opens when the engine oil level drops below a calibrated level. The engine control module (ECM) monitors the engine oil level signal circuit when the ignition is ON, and the engine is OFF. With the switch in the closed position, the ECM detects a low voltage on the signal circuit. With the switch in the open position, the ECM detects a high voltage on the signal circuit. When high voltage is detected on the signal circuit, the ECM will send a serial data message to the instrument panel cluster (IPC). The IPC will then display a message on the driver information center (DIC) or illuminate a low engine oil level lamp.

The following information determines the message sent from the ECM to the IPC

1. The Low Engine Oil Level message lamp is displayed only after the ECM detects a high voltage on the signal circuit for three consecutive ignition cycles, followed by an ignition OFF event from 15 minutes to greater than 50 minutes, depending on engine oil temperatures.
2. The Low Engine Oil Level message is turned OFF when the ECM detects a low voltage on the signal circuit after an ignition OFF event for greater than 90 seconds, followed by an ignition ON event for less than 1 second.

Schematic Reference

1. «Engine Mechanical Schematics»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-schematic-wiring-diagrams)
2. «Instrument Cluster Schematics»(/cadillac/ats/i-2012-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

1. «Instrument Cluster Description and Operation»(/cadillac/ats/i-2012-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
2. «Indicator/Warning Message Description and Operation»(/cadillac/ats/i-2012-2014/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/ats/i-2012-2014/remont/body-electrical/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information.

1. Verify proper engine oil level. If not at proper level Add oil as necessary. If at proper level
2. Ignition ON, verify the scan tool Engine Oil Level parameter reads OK. If not OK Refer to Circuit/System Testing. If OK
3. All OK.

Note. Verify proper engine oil level before continuing with diagnosis.

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B35 Engine Oil Level Switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohms between the ground circuit terminal 1 and ground. If 5 ohms or greater Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 5 ohms
3. Ignition ON.
4. Verify the scan tool Engine Oil Level Switch parameter reads Low. If the Engine Oil Level Switch parameter reads OK Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 Engine Control Module. If the Engine Oil Level Switch parameter reads Low
5. Install a 3A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.
6. Verify the scan tool Engine Oil Level Switch parameter reads OK. If the Engine Oil Level Switch parameter reads Low Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance on the circuit. If less than 2 ohms, replace the K20 Engine Control Module. If the Engine Oil Level Switch parameter reads OK
7. Test or replace the B35 Engine Oil Level Switch.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Engine Oil Level Indicator Switch Replacement»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-on-vehicle)
2. «Control Module References»(/cadillac/ats/i-2012-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for the ECM replacement, programming, and setup

Oil Consumption Diagnosis

Excessive oil consumption, not due to leaks, is the use of 0.9 L (1 qt) or greater of engine oil within 3 200 kilometers (2,000 miles). The causes of excessive oil consumption include the following conditions

1. External oil leaks Tighten bolts and/or replace gaskets and oil seals as necessary.
2. Incorrect oil level or improper reading of oil level indicator With the vehicle on a level surface, allow adequate drain down time and inspect for the correct oil level.
3. Improper oil viscosity Use recommended SAE viscosity for the prevailing temperatures.
4. Continuous high speed driving and/or severe usage
5. Crankcase ventilation system restrictions or malfunctioning components
6. Valve guides and/or valve stem oil seals worn, or the seal omitted Ream guides and install oversize service valves and/or new valve stem oil seals.
7. Piston rings broken, improperly installed, worn, or not seated properly Allow adequate time for rings to seat. Replace broken or worn rings, as necessary.
8. Piston improperly installed or mis-fitted

Oil Pressure Diagnosis and Testing

Special Tools

1. CH-48027 Digital Pressure Gauge
2. EN-21867-850 Oil Pressure Gauge Adapter

For equivalent regional tools, refer to Special Tools .

1. With the vehicle on a level surface, allow adequate drain down time of 2-3 minutes and measure for a low oil level. Add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
2. Run the engine, and verify low, or no oil pressure on the vehicle gauge or light. Listen for a noisy valve train or a knocking noise.
3. Inspect for the following: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil diluted by moisture or unburned fuel mixtures Improper oil viscosity for the expected temperature Incorrect or malfunctioning oil pressure sender Incorrect or malfunctioning oil pressure gauge Plugged oil filter Malfunctioning oil bypass valve
4. Remove the oil pressure sender or another engine block oil gallery plug.
5. Install EN-21867-850 adapter and CH-48027 gauge and measure the engine oil pressure.
6. Compare the readings to specifications. Refer to «Engine Mechanical Specifications (LCV)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-specifications__engine-mechanical-specifications-lcv) , «Engine Mechanical Specifications (LTG)»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-specifications__engine-mechanical-specifications-ltg) .
7. If the engine oil pressure is below specifications, inspect the engine for one or more of the following: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil pump worn or dirty Refer to «Balancer Shaft with Oil Pump Cleaning and Inspection»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-off-vehicle) . Oil pump screen loose, plugged, or damaged Oil pump screen O-ring seal missing or damaged Malfunctioning oil control valve solenoid Excessive bearing clearance Refer to «Crankshaft and Bearing Cleaning and Inspection»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-off-vehicle__crankshaft-and-bearing-cleaning-and-inspection) . Cracked, porous or restricted oil galleries Oil gallery plugs missing or incorrectly installed Refer to «Engine Block Assemble»(/cadillac/ats/i-2012-2014/remont/mechanical/#engine-mechanical-20l-ltg-or-25l-lcv-repair-instructions-off-vehicle__engine-block-assemble) . Broken lash adjusters

Oil Leak Diagnosis

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis (LCV)

Special Tools

EN 23951 Valve Manometer

For equivalent regional tools, refer to Special Tools .

1. Verify clean air cleaner.
2. Verify oil fill cap is in place.
3. Verify oil level indicator is installed.
4. Remove the oil level indicator. Install a EN 23951 valve manometer or equivalent into the oil level indicator hole.
5. Start the engine.
6. Check for slight vacuum. The vacuum level should be less than 3.377 kPa (1 in Hg).
7. If vacuum is higher, inspect and verify that the clean air hose from cam cover to air intake is not blocked or kinked.
8. If vacuum is in the normal range, remove PCV line from fresh air valve near the oil fill cap. Block the fresh air valve and also plug the fresh air hose. Vacuum should increase on the manometer. If held too long, vacuum will be drawn through the crankshaft seals creating a sucking sound.
9. If vacuum does not increase, the orifice between the camshaft cover assembly and the cylinder head assembly could be plugged.
10. If there is zero vacuum or pressure, verify compression of the engine.
11. If compression is normal, check for a blocked orifice between the camshaft cover assembly and the cylinder head assembly. Clean the orifice.

Crankcase Ventilation System Inspection/Diagnosis (LTG)

Special Tools

EN 23951 Valve Manometer

For equivalent regional tools, refer to Special Tools .

1. Verify clean air cleaner.
2. Verify oil fill cap is in place.
3. Verify oil level indicator is installed.
4. Remove the oil level indicator. Install a EN 23951 valve manometer or equivalent, into the oil level indicator hole.
5. Start the engine.
6. Check for slight vacuum. The vacuum level should be less than 3.377 kPa (1 in Hg).
7. If vacuum is higher, inspect and verify that the clean air hose from cam cover to air intake is not blocked or kinked.
8. If vacuum is in the normal range, remove the PCV line from the fresh air valve near oil fill cap. Block fresh air valve and also plug the fresh air hose. Vacuum should increase on the manometer. If held too long, vacuum will be drawn through the crankshaft seals creating a sucking sound.
9. If vacuum does not increase, the orifice in the camshaft cover assembly could be plugged. The valve is between the camshaft cover assembly and the cylinder head assembly.
10. If there is zero vacuum or pressure, verify compression of the engine.
11. If compression is normal, check for a blocked orifice at the camshaft cover assembly. Clean the orifice.
12. The hose from valve cover to the turbo is also for the positive crankcase ventilation (PCV) and is used for PCV flow under normal operation and only PCV flow during turbo boost conditions. If the hose is plugged, replace the PCV hose assembly and PCV fitting assembly at the turbocharger.

Diagnostic Aids

1. A chirping or squeal noise may be intermittent due to moisture on the drive belts or the pulleys. It may be necessary to spray a small amount of water on the drive belts in order to duplicate the customers concern. If spraying water on the drive belt duplicates the symptom, cleaning the belt pulleys may be the probable solution.
2. If the noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.
3. A chirping, squeal or whine noise may be caused by a loose or improper installation of a body or suspension component. Other items of the vehicle may also cause the noise.
4. The drive belts will not cause a whine noise.

Test Description

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

1. 2 The noise may not be engine related. This step is to verify that the engine is making the noise. If the engine is not making the noise do not proceed further with this table.
2. 3 The noise may be an internal engine noise. Removing the drive belts one at a time and operating the engine for a brief period will verify the noise is related to the drive belt. When removing the drive belt the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belts removed.
3. 4 Inspect all drive belt pulleys for pilling. Pilling is the small balls or pills or it can be strings in the drive belt grooves from the accumulation of rubber dust.
4. 6 Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
5. 10 Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut, spacer, or washer was installed.
6. 12 Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
7. 14 This test is to verify that the drive belt tensioner operates properly. If the drive belt tensioner is not operating properly, proper belt tension may not be achieved to keep the drive belt from slipping which could cause a squeal noise.
8. 15 This test is to verify that the drive belt is not too long, which would prevent the drive belt tensioner from working properly. Also if an incorrect length drive belt was installed, it may not be routed properly and may be turning an accessory drive component in the wrong direction.
9. 16 Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across two or three pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure for that pulley.
10. 17 This test is to verify that the pulleys are the correct diameter or width. Using a known good vehicle compare the pulley sizes.
11. 19 Replacing the drive belt when it is not damaged or there is not excessive pilling will only be a temporary repair.

Drive Belt Chirping, Squeal, and Whine Diagnosis

The accessory drive components can have an affect on engine vibration. Vibration from the engine operating may cause a body component or another part of the vehicle to make rumbling noise. Vibration can be caused by, but not limited to the A/C system over charged, the power steering system restricted or the incorrect fluid, or an extra load on the generator. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

The drive belt may have a rumbling condition that can not be seen or felt. Sometimes replacing the drive belt may be the only repair for the symptom.

If replacing the drive belt, completing the diagnostic table, and the noise is only heard when the drive belts are installed, there might be an accessory drive component with a failure. Varying the load on the different accessory drive components may aid in identifying which component is causing the rumbling noise.

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

1. 2 This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.
2. 3 This test is to verify that one of the drive belts is causing the rumbling noise or vibration. Rumbling noise may be confused with an internal engine noise due to the similarity in the description. Remove only one drive belt at a time if the vehicle has multiple drive belts. When removing the drive belts the water pump may not be operating and the engine may overheat. Also DTCs may set when the engine is operating with the drive belts removed.
3. 4 Inspecting the drive belts is to ensure that they are not causing the noise. Small cracks across the ribs of the drive belt will not cause the noise. Belt separation is identified by the plys of the belt separating and may be seen at the edge of the belt our felt as a lump in the belt.
4. 5 Small amounts of pilling is normal condition and acceptable. When the pilling is severe the drive belt does not have a smooth surface for proper operation.
5. 9 Inspecting of the fasteners can eliminate the possibility that the wrong bolt, nut, spacer, or washer was installed.
6. 11 This step should only be performed if the water pump is driven by the drive belt. Inspect the water pump shaft for being bent. Also inspect the water pump bearings for smooth operation and excessive play. Compare the water pump with a known good water pump.
7. 12 Accessory drive component brackets that are bent, cracked, or loose may put extra strain on that accessory component causing it to vibrate.

Drive Belt Rumbling and Vibration Diagnosis

If the drive belt repeatedly falls off the drive belt pulleys, this is because of pulley misalignment.

An extra load that is quickly applied on released by an accessory drive component may cause the drive belt to fall off the pulleys. Verify the accessory drive components operate properly.

If the drive belt is the incorrect length, the drive belt tensioner may not keep the proper tension on the drive belt.

Excessive wear on a drive belt is usually caused by an incorrect installation or the wrong drive belt for the application.

Minor misalignment of the drive belt pulleys will not cause excessive wear, but will probably cause the drive belt to make a noise or to fall off.

Excessive misalignment of the drive belt pulleys will cause excessive wear but may also make the drive belt fall off.

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

1. 2 This inspection is to verify the condition of the drive belt. Damage may of occurred to the drive belt when the drive belt fell off. The drive belt may of been damaged, which caused the drive belt to fall off. Inspect the belt for cuts, tears, sections of ribs missing, or damaged belt plys.
2. 4 Misalignment of the pulleys may be caused from improper mounting of the accessory drive component, incorrect installation of the accessory drive component pulley, or the pulley bent inward or outward from a previous repair. Test for a misaligned pulley using a straight edge in the pulley grooves across 2 or 3 pulleys. If a misaligned pulley is found refer to that accessory drive component for the proper installation procedure of that pulley.
3. 5 Inspecting the pulleys for being bent should include inspecting for a dent or other damage to the pulleys that would prevent the drive belt from not seating properly in all of the pulley grooves or on the smooth surface of a pulley when the back side of the belt is used to drive the pulley.
4. 6 Accessory drive component brackets that are bent or cracked will let the drive belt fall off.
5. 7 Inspecting of the fasteners can eliminate the possibility that a wrong bolt, nut , spacer, or washer was installed. Missing. loose, or the wrong fasteners may cause pulley misalignment from the bracket moving under load. Over tightening of the fasteners may cause misalignment of the accessory component bracket.
6. 13 The inspection is to verify the drive belt is correctly installed on all of the drive belt pulleys. Wear on the drive belt may be caused by mis-positioning the drive belt by one groove on a pulley.
7. 14 The installation of a drive belt that is too wide or too narrow will cause wear on the drive belt. The drive belt ribs should match all of the grooves on all of the pulleys.
8. 15 This inspection is to verify the drive belt is not contacting any parts of the engine or body while the engine is operating. There should be sufficient clearance when the drive belt accessory drive components load varies. The drive belt should not come in contact with an engine or a body component when snapping the throttle.

Drive Belt Falls Off and Excessive Wear Diagnosis

Drive Belt Tensioner Diagnosis

Drive Belt Tensioner Diagnosis

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Mechanical Schematics
• COMPONENT CONNECTOR END VIEWS - INDEX
• Vacuum Operated Engine Mounts Description and Operation
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Power Mode Mismatch
• Diagnostic Repair Verification
• Engine Mount Vacuum Valve Replacement
• Oil Pump Flow Control Valve Replacement
• Engine Mechanical Specifications (LCV)
• Engine Mechanical Specifications (LTG)
• Disassembled Views (LCV)
• Engine Component Description (LCV)
• Camshaft Position Actuator and Camshaft Replacement - Intake
• Symptoms - Engine Controls
• Cylinder Head Cleaning and Inspection
• Special Tools
• Instrument Cluster Schematics
• Balancer Shaft with Oil Pump Cleaning and Inspection
• Crankshaft and Bearing Cleaning and Inspection
• Engine Block Assemble
• Belt Dressing Caution
• Fastener Caution
• Fastener Tightening Specifications (LCV)
• Fastener Tightening Specifications (LTG)
• Vibration Analysis - Engine
• Water Pump Replacement (LFX)
• Water Pump Replacement (LCV)
• Water Pump Replacement (LTG)
• Oil Pressure Diagnosis and Testing
• Base Engine Misfire without Internal Engine Noises
• Base Engine Misfire with Abnormal Internal Lower Engine Noises
• Base Engine Misfire with Abnormal Valve Train Noise
• Base Engine Misfire with Coolant Consumption
• Base Engine Misfire with Excessive Oil Consumption
• Engine Noise on Start-Up, but Only Lasting a Few Seconds
• Upper Engine Noise, Regardless of Engine Speed
• Lower Engine Noise, Regardless of Engine Speed
• Engine Noise Under Load
• Engine Will Not Crank - Crankshaft Will Not Rotate
• Engine Compression Test
• Oil Consumption Diagnosis
• Oil Leak Diagnosis
• Drive Belt Chirping, Squeal, and Whine Diagnosis
• Drive Belt Tensioner Diagnosis
• Turbocharger Leaking Fluids Externally
• Turbocharger Noise
• Turbocharger Smoke or Smell
• Turbocharger Loss of Boost Pressure
• Crankcase Ventilation System Inspection/Diagnosis (LCV)
• Crankcase Ventilation System Inspection/Diagnosis (LTG)