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Home/Cadillac/Escalade/Cadillac Escalade GMT900 (2006-2014)/Repair manual/Testing & Diagnostics/Engine Control System & Fuel System - 5.3l, 6.0l, 6.2l - DT…
Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Control System & Fuel System - 5.3l, 6.0l, 6.2l - DTC p1255 to DTC p3449 Cadillac Escalade GMT900

Testing & Diagnostics ~11859 words

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

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.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

DTCs P064A and P1255 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P064A and P1255 are Type A DTCs.

Diagnostic Aids

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.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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 Testing

  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/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-dtc-p0010-to-dtc-p0231p025a) .
  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.

Repair Procedures

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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 percent.
  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 electronic brake control module (EBCM) sends a message to the ECM indicating that a failure has occurred in the EBCM.
  2. Engine misfire is detected and DTC P0300 sets with the MIL illuminated.

P1381

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

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

Circuit/System Verification

  1. Engine idling, observe the EBCM DTC information with a scan tool. EBCM DTCs should not set. If a DTC sets, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis. If there are no EBCM DTCs set, refer to the following: «Symptoms - Antilock Brake System»(/cadillac/escalade/gmt900-2006-2014/remont/anti-locktraction-control/#antilock-brake-system-hybrid-hp2-with-electronic-brake-distribution-vehicle-stability-system__symptoms-antilock-brake-system) for the ABS - Hybrid «Symptoms - Antilock Brake System»(/cadillac/escalade/gmt900-2006-2014/remont/anti-locktraction-control/#antilock-brake-system-non-hybrid-less-than-3900-kg-8600-lb-gvw-with-ebd-vses__symptoms-antilock-brake-system) for the ABS - Non-Hybrid Less than 3900 kg (8600 lb) GVW «Symptoms - Antilock Brake System»(/cadillac/escalade/gmt900-2006-2014/remont/anti-locktraction-control/#antilock-brake-system-non-hybrid-greater-thanequal-to-3900-kg-8600-lb-gvw-with-tcs-ves__symptoms-antilock-brake-system) for the ABS - Non-Hybrid Greater than/Equal to 3900 kg (8600 lb) GVW
  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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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.

Conditions for Clearing the MIL/DTC

DTC P1400 is a Type A DTC.

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Description and Operation

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 runtime 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/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-diagnostic-information-and-procedures) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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
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 1 s.

P2101

The actual throttle position does not match the predicted throttle position for greater than 1 s.

P2119

The ECM detects that the throttle blade did not return to the default position when the TAC motor is de-energized for greater than 1 s.

P2176

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.

P2119

  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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for Engine Control Module replacement, programming, and setup

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 s.
  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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 Voltage, Run/Crank 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.

Typical Scan Tool Data

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Ignition ON, engine OFF, and run/crank and powertrain relay are commanded ON
Ignition 1 Voltage, Run/Crank 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 run/crank 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/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-wiring-schematic-diagrams)
  2. «Power Distribution Schematics»(/cadillac/escalade/gmt900-2006-2014/remont/body-electrical/#wiring-systems-and-power-management-schematic-and-wiring-harness-routing-diagrams)

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Probing Electrical Connectors»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__probing-electrical-connectors)
  6. «Electrical Center Identification Views»(/cadillac/escalade/gmt900-2006-2014/remont/electrical-component-locations/#wiring-systems-and-power-management-component-locator-electrical-center-identification-views)

DTC Type Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 35616 GM-Approved Terminal Test Kit

  1. If DTCs P0685, P0689, or P0690 are set, diagnose those DTCs first.
  2. Ignition ON, engine OFF, observe both the Ignition 1 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 scan tool Ignition 1 Signal and the EC Ignition Relay Feedback 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. Ignition ON, connect a 20 A fused jumper wire between B+ and the applicable ignition voltage circuit terminal 87. Verify that the applicable scan tool parameter displays between 9-14 V. If 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 appropriate relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.
CircuitShort to GroundHigh ResistanceOpenShort to VoltageSignal Performance
APP Sensor 1 5 V ReferenceP2122P2138P2122P2123P2138
APP Sensor 2 5 V ReferenceP2127P2138P2127P2128P2138
APP Sensor 1 SignalP2122P2138P2122P2123P2138
APP Sensor 2 SignalP2127P2138P2127P2128P2138
APP Sensor 1 Low ReferenceP2138P2123P2138
APP Sensor 2 Low ReferenceP2138P2128P2138
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: The engine is operating at idle. Parameter Normal Range: APP Sensor 1 0.88-1.08 V Parameter Normal Range: APP Sensor 2 0.39-0.59 V
APP Sensor 1 5 V Reference0.00 V0.00 V2.7-3.7 V
APP Sensor 2 5 V Reference0.00 V0.00 V1-2 V
APP Sensor 1 Signal0.00 V0.00 V4-5 V
APP Sensor 2 Signal0.00 V0.00 V4-5 V
APP Sensor 1 Low Reference4-5 V
APP Sensor 2 Low Reference4-5 V

APP Sensor 1 and 2

The accelerator pedal assembly contains 2 accelerator pedal position (APP) sensors. The APP sensors are mounted to the accelerator pedal assembly and are not serviceable. The APP sensors provide a signal voltage that changes relative to pedal position. The engine control module (ECM) supplies each APP sensor with a 5 V reference circuit, a low reference circuit, and a signal circuit.

P2120, P2122, P2123, P2125, P2127, P2128

  1. DTC P0641 or P0651 is not set.
  2. The ignition is ON or the engine is running.
  3. The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
  4. DTC P2120, P2122, P2123, P2125, P2127, P2128 run continuously when the above conditions are met.

P2138

  1. DTC P0641, P0651, P2120, P2125 are not set.
  2. The ignition is ON or the engine is running.
  3. The run/crank or powertrain relay voltage is greater than 6.0 V and reduced power is not active.
  4. DTC P2138 runs continuously when the above conditions are met.

P2120

The APP sensor 1 voltage is less than 0.46 V or greater than 4.7 V for greater than 0.2 s.

P2122

The ECM detects that the APP sensor 1 voltage is less than 0.46 V for greater than 0.2 s.

P2123

The ECM detects that the APP sensor 1 voltage is greater than 4.75 V for greater than 0.2 s.

P2125

The APP sensor 2 voltage is less than 0.32 V or greater than 2.6 V for greater than 0.2 s.

P2127

The ECM detects that the APP sensor 2 voltage is less than 0.32 V for greater than 0.2 s.

P2128

The ECM detects that the APP sensor 2 voltage is greater than 2.6 V for greater than 0.2 s.

P2138

The voltage difference between APP sensor 1 and APP sensor 2 exceeds a predetermined value for greater than 1 s.

  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.

A high resistance condition on the accelerator pedal sensor circuits could cause a DTC to set.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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. Verify that DTC P0641 or P0651 are not set. If a DTC is set, refer to «DTC P0641 or P0651 (ECM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-dtc-p0300-to-p1175) for further diagnosis.
  2. Observe the scan tool APP Sensor 1 and 2 voltage parameters. Verify both of the APP sensor voltages are between 0.32-4.75 V.
  3. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. DTCs P2120, P2122, P2123, P2125, P2127, P2128, or P2138 should not set.
  4. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs P2120, P2122, P2123, P2125, P2127, P2128, or P2138 should not set.
  5. Observe the scan tool APP sensor 1 and 2 parameter. The scan tool should display Agree.
  6. 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.
  7. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P2120 or P2125 are not the only APP sensor DTCs set. If DTC P2120 or P2125 are the only DTCs set, replace the ECM.
  8. 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 accelerator pedal.
  2. Ignition OFF for 1 minute, test for less than 5 ohms between the appropriate low reference circuit terminal listed below and ground. APP sensor 1 terminal F or 4 APP sensor 2 terminal A or 5 If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit/connections test normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 V between the appropriate 5 V reference circuit terminal listed below and ground. APP sensor 1 terminal D or 2 APP sensor 2 terminal C or 1 If less than the specified range, test the 5 V reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM. If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.
  4. Observe the scan tool APP sensor 1 voltage parameter. Verify the voltage is less than 0.3 V. If greater than the specified range, test the signal circuit terminal E or 3 for a short to voltage. If the circuit/connections test normal, replace the ECM.
  5. Observe the scan tool APP sensor 2 voltage parameter. Verify the voltage is less than 0.3 V. If greater than the specified range, test the signal circuit terminal B or 6 for a short to voltage. If the circuit/connections test normal, replace the ECM.
  6. Connect a 3 A fused jumper wire between the APP sensor 1 signal circuit terminal E or 3 and the 5 V reference circuit terminal C or 1. Verify the APP sensor 1 voltage parameter is greater than 4.8 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  7. Connect a 3 A fused jumper wire between the APP sensor 2 signal circuit terminal B or 6 and the 5 V reference circuit terminal C or 1. Verify the APP sensor 2 voltage parameter is greater than 4.8 V. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the ECM.
  8. If all circuits/connections test normal, test or replace the Accelerator Pedal Assembly.

Perform the Diagnostic Repair Verification after completing the repair.

  1. «Accelerator Pedal Position Sensor Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 V, or less than 18 V.
  9. The engine run time is greater than 100 s.
  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 P219A and P219B are Type B DTCs.

DTCs P219A and P219B 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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Troubleshooting with a Test Lamp»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__troubleshooting-with-a-test-lamp)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-dtc-p0010-to-dtc-p0231p025a) or «DTC P0107 or P0108»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-dtc-p0010-to-dtc-p0231p025a) .
  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/escalade/gmt900-2006-2014/remont/exhaust/#engine-exhaust-system__symptoms-engine-exhaust) .
  9. Test the fuel injectors for improper operation. Refer to «Fuel Injector Diagnosis (CH47976)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel Injector Diagnosis (J39021 or Scan Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) .
  10. Test for fuel contamination. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-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/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-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/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 (CH47976)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel Injector Diagnosis (J39021 or Scan Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) Water intrusion in the B52 HO2S harness connector Low fuel system pressure-Refer to «Fuel System Diagnosis (w/o FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel System Diagnosis (FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) Exhaust leaks near the B52 HO2S Engine vacuum leaks Contaminated B52 HO2S - Silicon An engine mechanical condition- «Symptoms - Engine Mechanical»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-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 (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (2500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (2500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  5. «Heated Oxygen Sensor Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 (CH47976)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel Injector Diagnosis (J39021 or Scan Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) Water intrusion in the B52 HO2S harness connector High fuel system pressure-Refer to «Fuel System Diagnosis (w/o FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel System Diagnosis (FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) Fuel that is contaminated-Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-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 (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (2500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (2500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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 «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  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 MISC IGN 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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for a overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

To improve shift feel, the transmission control module (TCM) is constantly sending the engine control module (ECM) serial data messages with information regarding it's request for modifying engine speed or torque. The serial data messages are sent through two circuits which are part of a communication network called the controller area network (CAN). The ECM sets DTC P2544 when it detects a discrepancy in the structure of the message causing the integrity of the message to be questioned.

An intermittent fault in the CAN circuits will cause the ECM to set DTC P2544.

  1. The engine run time is greater than 0.5 s.
  2. No other CAN errors are present.

The ECM detects that the engine speed and torque modification messages from the TCM are either corrupted or intermittently missing for greater than 4 s.

  1. DTC P2544 is a Type B DTC.
  2. The TCM commands maximum line pressure during shifts, which results in harsh shifts.
  3. The TCM freezes adaptive functions.

DTC P2544 is a Type B DTC.

DTC Type Reference

  1. DTC P2544 is an informational DTC. Diagnose all other engine control DTCs prior to DTC P2544. Refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) .
  2. If there are no other engine controls DTCs, diagnosis is accomplished by looking for an intermittent CAN circuit fault. Refer to «Scan Tool Does Not Communicate with High Speed GMLAN Device»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#data-communication-system) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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
Battery Voltage - Relay Switch Side13
Fuel Pump Supply Voltage132
Fuel Pump Relay ControlP2632P2632P2632
Fuel Pump Relay GroundP2632
Fuel Pump Ground3
1 Open fuel pump fuse 2 Fuel pump operates continuously, then discharged battery 3 Fuel pump operates will not operate

The control module enables the secondary fuel pump relay when the ignition switch is turned ON. The control module will disable the secondary fuel pump relay within 2 seconds unless the control module detects ignition reference pulses. The control module continues to enable the secondary fuel pump relay as long as ignition reference pulses are detected. The control module disables the secondary fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.

The control module monitors the voltage on the secondary fuel pump relay control circuit. If the control module detects an incorrect voltage on the secondary fuel pump relay control circuit, a fuel pump relay 2 control DTC sets.

  1. The ignition voltage is between 9-18 volts.
  2. DTC P2632 runs continuously when the above condition is met.
  1. The control module detects that the commanded state of the driver and the actual state of the control circuit do not match.
  2. The above condition is met for a minimum of 2.5 seconds.

DTCs P2632 is a Type B DTC.

DTCs P2632 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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 43244 Relay Puller Pliers. See Special Tools .

IMPORTANTAn open or a short to voltage in the control circuit will cause both the Ckt. Open Test Status and the Ckt. Short Volts Test Status parameters to display Fault.
  1. Ignition ON, command the fuel pump relay ON and OFF with a scan tool while observing the following control circuit status parameters: Fuel Pump Relay Ckt. Short Gnd Test Status Fuel Pump Relay Ckt. Open Test Status Fuel Pump Relay Ckt. Short Volts Test Status
  2. Each parameter should toggle between OK and Not Run or Not Run and OK.
  1. Ignition OFF, disconnect the secondary fuel pump relay.
  2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal and B+. If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
  3. Verify that a test lamp does not illuminate between the ground circuit terminal and the control circuit terminal. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Remove the test lamp.
  5. Command the fuel pump relay ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is OK. If not the specified value, test the secondary fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  6. Install a 3 A fused jumper wire between the secondary fuel pump relay control circuit terminal and the ground circuit terminal. Command the fuel pump ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is Fault. If not the specified value, test the secondary fuel pump relay control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  7. If all circuits test normal, test or replace the secondary fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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
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 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/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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 OFF, test for less than 5.0 ohms between the G12 fuel pump low reference circuit terminal A 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 D and the low reference circuit terminal A.
  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 (w/o FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-diagnosis) or «Fuel System Diagnosis (FPCM)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-troubleshooting-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 (2500 LWB - 43.5L (11.5 gal) Tank Rear)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (2500 LWB - 98.4L (26 gal) Tank Front)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 SWB - 98.4L (26 gal) Tank + E85)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 LWB - 117.3L (31 gal) Tank + E85)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provide an overview of each diagnostic category.

The secondary fuel pump is located in the rear fuel tank. The secondary fuel pump is powered by a secondary fuel pump relay. Fuel is transferred from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to the primary fuel pump. The secondary fuel pump relay is controlled by the engine control module (ECM). If the engine is running the secondary fuel pump is normally ON.

  1. The engine is running.
  2. The vehicle speed is 0 km/h (0 mph).
  3. The ignition voltage is between 9-18 volts.
  4. The transfer pump is activated.
  5. A slosh delay of 20 seconds has passed.
  6. DTC P2636 runs continuously when the above conditions are met.

The ECM does not detect a change of 3 L (0.7925 gal), in both the primary and the secondary fuel level sensors, with the secondary pump commanded ON for 200 seconds.

DTC P2636 is a Type B DTC.

DTC P2636 is a Type B DTC.

Schematic Reference

Connector End View Reference

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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 43244 Relay Puller Pliers. See Special Tools .

IMPORTANTAn open or a short to voltage in the control circuit will cause both the Ckt. Open Test Status and the Ckt. Short Volts Test Status parameters to display Fault.

Ignition ON, command the fuel pump relay ON and OFF with a scan tool while observing the following control circuit status parameters

  1. Fuel Pump Relay Ckt. Short Gnd Test Status
  2. Fuel Pump Relay Ckt. Open Test Status
  3. Fuel Pump Relay Ckt. Short Volts Test Status

Each parameter should toggle between OK and Not Run or Not Run and OK.

  1. Ignition OFF, disconnect the fuel pump relay.
  2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal 85 and B+. If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
  3. Verify that a test lamp does not illuminate between the ground circuit terminal 85 and the control circuit terminal 86. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Remove the test lamp.
  5. Command the fuel pump relay ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is OK. If not the specified value, test the fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the fuel pump relay control circuit terminal 86 and the ground circuit terminal 85. Command the fuel pump ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is Fault. If not the specified value, test the fuel pump relay control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  7. Inspect the fuel pump fuse. If the fuel pump fuse is open, test for the following conditions: A short to ground in the relay switch B+ circuit A short to ground in the supply voltage circuit of the fuel pump If the above circuits test normal, replace the fuel tank module.
  8. Verify that a test light illuminates between the B+ circuit and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  9. Connect a 15A fused jumper wire between the B+ circuit and the supply voltage circuit of the fuel pump. Verify the fuel pump is activated. If the fuel pump does not activate, test for the following conditions: An open/high resistance in the supply voltage circuit of the fuel pump An open/high resistance in the ground circuit of the fuel pump If the above circuits test normal, replace the fuel tank module.
  10. If all circuits test normal, test or replace the fuel pump relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Fuel Tank Fuel Pump Module Replacement (2500 LWB - 43.5L (11.5 gal) Tank Rear)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (2500 LWB - 98.4L (26 gal) Tank Front)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 SWB - 98.4L (26 gal) Tank + E85)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 Series)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions) or «Fuel Tank Fuel Pump Module Replacement (1500 LWB - 117.3L (31 gal) Tank + E85)»(/cadillac/escalade/gmt900-2006-2014/remont/testing-diagnostics/#engine-control-system-fuel-system-53l-60l-62l-repair-instructions)
  2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions) or «Relay Replacement (Within an Electrical Center)»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  3. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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
Ignition 1 VoltageP0102, P0443, P3401, P3425, P3441, P3449P3400, P3401, P3425, P3441, P3449P3400
Cylinder 1 Deactivation Solenoid Control Circuit 1P0300, P3401P0300, P3400, P3401P0300, P3401P3400
Cylinder 4 Deactivation Solenoid Control Circuit 2P0300, P3425P0300, P3400, P3425P0300, P3425P3400
Cylinder 6 Deactivation Solenoid Control Circuit 3P0300, P3441P0300, P3400, P3441P0300, P3441P3400
Cylinder 7 Deactivation Solenoid Control Circuit 4P0300, P3449P0300, P3400, P3449P0300, P3449P3400

The cylinder deactivation system is used to deactivate 4 cylinders of the engine under light load driving conditions. The engine control module (ECM) commands the cylinder deactivation solenoids ON to deactivate engine cylinders 1, 7, 6, and 4, switching to 4 cylinders or V4 mode. The cylinder deactivation solenoids controls the oil flow to the appropriate valve lifters. The engine operates on 8 cylinders or V8 mode, during engine starting, engine idling, and medium to heavy throttle conditions.

Ignition voltage is supplied directly to the 4 cylinder deactivation solenoids. The engine control module (ECM) controls the 4 cylinder deactivation solenoids by grounding the control circuit with a solid state device called a driver.

The Cylinder Deactivation System Performance diagnostic is a test of the internal mechanical condition of the engine, during operation in V4 mode. The engine control module (ECM) determines the internal mechanical condition of the engine through the actual measured values of the mass airflow (MAF) sensor, the intake manifold absolute pressure (MAP) sensor, and the throttle position sensor. The actual measured values of the 3 sensors are then compared to the calculated values for V4 mode, stored in the ECM. If the measured values are incorrect for V4 mode, the ECM will set DTC P3400, and will return to V8 mode operation.

  1. DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0119, P0335, and P0336 are not set.
  2. The engine speed is between 450-6,400 RPM.
  3. The IAT Sensor parameter is between -7 and +125°C (+19 and +257°F).
  4. The ECT Sensor parameter is between 70- 125°C (158-257°F).
  5. Time in V8 mode is more than 2 seconds.
  6. Time in V4 mode is more than 2 seconds.
  7. This DTC runs continuously within the enabling conditions.

The ECM detects that the actual measured values from the MAF sensor, MAP sensor, and throttle position sensor, are not within the range of the calculated values for V4 mode.

  1. DTC P3400 is a Type B DTC.
  2. The engine will return to V8 mode.

DTC P3400 is a Type B DTC.

  1. This DTC will not set during engine idling conditions. The vehicle will need to be driven for the DTC to set.
  2. The valve lifter oil manifold solenoids are assigned to the following engine cylinders: Solenoid #1 = Cylinder #1 Solenoid #2 = Cylinder #4 Solenoid #3 = Cylinder #6 Solenoid #4 = Cylinder #7

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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

EN-46999 Displacement On Demand Tester. See Special Tools .

For equivalent regional tools, refer to Special Tools .

  1. Ignition ON, observe the scan tool DTC information. Verify that DTC P0201-P0208, P0351-P0358, P3401, P3425, P3441, or P3449 is not set. If a DTC is set, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(/cadillac/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-trouble-code-dtc-list) for further diagnosis.
  2. Engine idling at the normal operating temperature. Verify there is no abnormal engine noise. If there is an abnormal engine noise, refer to «Symptoms - Engine Mechanical»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-diagnostic-information-and-procedures) for further diagnosis.
  3. Perform the «Cylinder Deactivation (Active Fuel Management) System Compression Test»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-diagnostic-information-and-procedures__cylinder-deactivation-active-fuel-management-system) . The Cylinder Deactivation System should pass the compression test.
  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.
  1. Ignition OFF, remove the valve lifter oil manifold assembly ignition fuse from the underhood fuse block.
  2. Connect a DMM between the ignition circuit fuse terminal going to the valve lifter oil manifold assembly and the ECM housing.
  3. Ignition ON, command each Cylinder 1, 4, 6, and 7 Deactivation solenoid ON and OFF with the scan tool. Verify the resistance of each solenoid is between 11-18 ohms with the solenoid commanded ON. If greater than the specified range for all cylinder deactivation solenoids, test the ignition circuit for an open/high resistance. If greater than the specified range for one or more but not all cylinder deactivation solenoids, test both the control circuit and ignition circuit for an open/high resistance or an open/high resistance in the cylinder deactivation solenoid. If the circuits and solenoid test normal replace the ECM.
  4. If all circuits and components test normal, refer to «Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-diagnostic-information-and-procedures__cylinder-deactivation-active-fuel-management-valve) for further mechanical diagnosis of valve lifter oil manifold assembly.

Component Testing

Static Test

  1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
  2. Connect the harness that is labeled resistance from the displacement on demand (DOD) tester to the valve lifter oil manifold connector.
  3. Connect the power leads from the DOD tester to B+ and ground. Test for 11-18 ohms on each valve lifter oil manifold solenoid. If not within the specified range for each solenoid, replace the valve lifter oil manifold assembly.
  4. Test for infinite resistance between each valve lifter oil manifold circuit terminal listed and the valve lifter oil manifold housing. If less than infinite resistance, replace the valve lifter oil manifold assembly.

Dynamic Test

  1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
  2. Connect the cable that is labeled power from the displacement on demand DOD tester to the connector.
  3. Connect the power leads from the DOD tester to B+ and ground.
  4. Command each valve lifter oil manifold solenoid ON and OFF using the DOD tester. You should be able to hear each solenoid turn ON and OFF. If the function does not perform as specified, replace the valve lifter oil manifold assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Valve Lifter Oil Manifold Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-repair-instructions-on-vehicle)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/escalade/gmt900-2006-2014/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/escalade/gmt900-2006-2014/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
Ignition 1 VoltageP0102, P0443, P3401, P3425, P3441, P3449P3400, P3401, P3425, P3441, P3449P3400
Cylinder 1 Deactivation Solenoid Control Circuit 1P0300, P3401P0300, P3400, P3401P0300, P3401P3400
Cylinder 4 Deactivation Solenoid Control Circuit 2P0300, P3425P0300, P3400, P3425P0300, P3425P3400
Cylinder 6 Deactivation Solenoid Control Circuit 3P0300, P3441P0300, P3400, P3441P0300, P3441P3400
Cylinder 7 Deactivation Solenoid Control Circuit 4P0300, P3449P0300, P3400, P3449P0300, P3449P3400
CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Component Commanded OFF Parameter Normal Range: The following illustrates the normal parameter state with no circuit conditions: Component OFF - OK for Open/Low Voltage test and Not Run for High Voltage Test Component ON - Not Run for Open/Low Voltage Test and OK for High Voltage Test
Ignition VoltageMalfunctionMalfunction
Cylinder 1, 4, 6, or 7 Deactivation Solenoid ControlMalfunctionMalfunctionNot Run

Cylinder 1, 4, 6, or 7 Deactivation Solenoid Valve Control Circuit Open, Low and High Voltage Test Status - Component Commanded OFF

CircuitShort to GroundOpenShort to Voltage
Operating Conditions: Component Commanded ON Parameter Normal Range: The following illustrates the normal parameter state with no circuit conditions: Component OFF - OK for Open/Low Voltage test and Not Run for High Voltage Test Component ON - Not Run for Open/Low Voltage Test and OK for High Voltage Test
Ignition VoltageNot RunNot Run
Cylinder 1, 4, 6, or 7 Deactivation Solenoid ControlNot RunNot RunMalfunction

Cylinder 1, 4, 6, or 7 Deactivation Solenoid Valve Control Circuit Open, Low and High Voltage Test Status - Component Commanded ON

The cylinder deactivation system is used to deactivate 4 cylinders of the engine under light load driving conditions. The engine control module (ECM) commands the cylinder deactivation solenoids ON to deactivate engine cylinders 1, 7, 6, and 4, switching to 4 cylinders or V4 mode. The cylinder deactivation solenoids controls the oil flow to the appropriate valve lifters. The engine operates on 8 cylinders or V8 mode, during engine starting, engine idling, and medium to heavy throttle conditions.

Ignition voltage is supplied directly to the 4 cylinder deactivation solenoids. The engine control module (ECM) controls the 4 cylinder deactivation solenoids by grounding the control circuit with a solid state device called a driver.

  1. The engine speed is greater than 400 RPM.
  2. The ignition voltage is between 9-18 volts.
  3. DTC P3401, P3425, P3441, and P3449 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 5 s.

  1. DTC P3401, P3425, P3441, and P3449 are Type B DTCs.
  2. The engine will return to V8 mode.
  3. The fuel injector will turn OFF for the cylinder that has a cylinder deactivation DTC set, resulting in an engine misfire.

DTC P3401, P3425, P3441, and P3449 are Type B DTCs.

The valve lifter oil manifold solenoids are assigned to the following engine cylinders

  1. Solenoid #1 = Cylinder #1
  2. Solenoid #2 = Cylinder #4
  3. Solenoid #3 = Cylinder #6
  4. Solenoid #4 = Cylinder #7

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/escalade/gmt900-2006-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/escalade/gmt900-2006-2014/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

EN-46999 Displacement On Demand Tester. See Special Tools .

For equivalent regional tools, refer to Special Tools .

  1. Ignition ON, command the appropriate cylinder deactivation solenoid ON and OFF while observing the following status parameters with a scan tool: Cyl. 1, 4, 6, or 7 Deact. Sol. Ckt Open Test Status Cyl. 1, 4, 6, or 7 Deact. Sol. Ckt Short Gnd Test Status Cyl. 1, 4, 6, or 7 Deact. Sol. Ckt Short Volts Test Status Each parameter should display OK or Not Run
  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. Ignition OFF, remove the intake manifold. Refer to «Intake Manifold Replacement (Without AFM)»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-repair-instructions-on-vehicle) or «Intake Manifold Replacement (With AFM)»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-repair-instructions-on-vehicle) .
  2. Disconnect the harness connector at the valve lifter oil manifold assembly.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal E and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
  4. Verify that a test lamp does not illuminate between the ignition circuit terminal E and the appropriate cylinder deactivation solenoid control circuit terminal listed below. Cylinder deactivation solenoid valve 1 terminal C Cylinder deactivation solenoid valve 2 terminal A Cylinder deactivation solenoid valve 3 terminal B Cylinder deactivation solenoid valve 4 terminal D If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  5. Remove the test lamp.
  6. Command the appropriate cylinder deactivation solenoid ON with a scan tool. Verify the scan tool Cylinder Deactivation Solenoid Valve Control Circuit High Voltage Test Status parameter displays OK. If not the specified value, test the appropriate control circuit listed below for a short to voltage. If the circuit tests normal, replace the ECM. Cylinder deactivation solenoid valve 1 terminal C Cylinder deactivation solenoid valve 2 terminal A Cylinder deactivation solenoid valve 3 terminal B Cylinder deactivation solenoid valve 4 terminal D
  7. Install a 3 A fused jumper wire between the appropriate control circuit terminal listed below and the ignition circuit terminal E. Command the appropriate cylinder deactivation solenoid ON with a scan tool. Verify the scan tool Cylinder Deactivation Solenoid Valve Control Circuit High Voltage Test Status parameter displays Malfunction. Cylinder deactivation solenoid valve 1 terminal C Cylinder deactivation solenoid valve 2 terminal A Cylinder deactivation solenoid valve 3 terminal B Cylinder deactivation solenoid valve 4 terminal D If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  8. If all the circuits test normal, test or replace the valve lifter oil manifold assembly.

Static Test

  1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
  2. Connect the harness that is labeled resistance from the displacement on demand (DOD) tester to the valve lifter oil manifold connector.
  3. Connect the power leads from the DOD tester to B+ and ground. Test for 11-18 ohms on each valve lifter oil manifold solenoid. If not within the specified range for each solenoid, replace the valve lifter oil manifold assembly.
  4. Test for infinite resistance between each valve lifter oil manifold circuit terminal and the valve lifter oil manifold housing. If less than infinite resistance, replace the valve lifter oil manifold assembly.

Dynamic Test

  1. Ignition OFF, disconnect the harness connector at the valve lifter oil manifold assembly.
  2. Connect the cable that is labeled power from the displacement on demand DOD tester to the connector.
  3. Connect the power leads from the DOD tester to B+ and ground.
  4. Command each valve lifter oil manifold solenoid ON and OFF using the DOD tester. You should be able to hear each solenoid turn ON and OFF. If the function does not perform as specified, replace the valve lifter oil manifold assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Valve Lifter Oil Manifold Replacement»(/cadillac/escalade/gmt900-2006-2014/remont/mechanical/#engine-mechanical-53l-60l-62l-repair-instructions-on-vehicle)
  2. «Control Module References»(/cadillac/escalade/gmt900-2006-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for ECM replacement, setup, and programming

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Engine Controls Schematics
• Component Connector End Views
• Fuel System Description
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• DTC P0231, P0232, or P023F
• Diagnostic Repair Verification
• Diagnostic Trouble Code (DTC) List - Vehicle
• Symptoms - Antilock Brake System
• Symptoms - Antilock Brake System
• Symptoms - Antilock Brake System
• Engine Control Module Description
• Crankcase Ventilation System Inspection/Diagnosis
• Symptoms - Engine Exhaust
• Symptoms - Engine Mechanical
• Throttle Body Assembly Replacement
• Battery Inspection/Test
• Power Distribution Schematics
• Probing Electrical Connectors
• Electrical Center Identification Views
• Relay Replacement (Attached to Wire Harness)
• DTC P0641 or P0651 (ECM)
• Troubleshooting with a Test Lamp
• Fuel Injector Diagnosis (CH47976)
• Heated Oxygen Sensor Wiring Repairs
• Heated Oxygen Sensor Resistance Learn Reset Caution
• Scan Tool Does Not Communicate with High Speed GMLAN Device
• Special Tools
• Oil Pressure Diagnosis and Testing
• Valve Lifter Oil Filter Replacement
• Cylinder Deactivation (Active Fuel Management) System Compression Test
• Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing

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