PRE-RELEASE
DTC P2600-P2603
| DTC P2600-P2603 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC P2600
Auxiliary Coolant Pump Relay Control Circuit
DTC P2601
Auxiliary Coolant Pump Performance
DTC P2602
Auxiliary Coolant Pump Relay Control Circuit Low Voltage
DTC P2603
Auxiliary Coolant Pump Relay Control Circuit High Voltage
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
| Auxiliary Coolant Pump Relay Control | P2602 | P2600 | P2603 | - |
| Ground | - | P2600 | - | - |
| Circuit/System Description |
The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump circuit board (PCB) relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.
| Conditions for Running the DTC |
P2600, P2602, or P2603
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The engine speed is greater than 80 RPM.
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The ignition voltage is between 10-18 V.
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The ECM has commanded the pump ON and OFF at least once during the ignition cycle.
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The DTCs run continuously once the above conditions are met.
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P2601
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DTC P0111, P0112, P0113, P0116, P0117, P0118, P0119, P2600, P2602, or P2603 is not set.
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The ignition is OFF.
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The engine coolant temperature (ECT) at engine shut down is warmer than 110 °C (230 °F).
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The auxiliary coolant pump is enabled.
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The DTC runs continuously once the conditions above are met for greater than 30 S.
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| Conditions for Setting the DTC |
P2600
The ECM detects the pump control circuit is open. The condition exists for 4 S or a cumulative of 30 S.P2601
The ECM detects that the ECT decreases less than 2 °C (4 °F) within 60 seconds. The condition exists for 4 S or a cumulative of 30 S.P2602
The ECM detects the pump control circuit is shorted to ground. The condition exists for 4 seconds or a cumulative of 30 seconds.P2603
The ECM detects the pump control circuit is shorted to voltage. The condition exists for 4 seconds or a cumulative of 30 seconds.| Action Taken When the DTC Sets |
The DTCs are Type C DTCs.
| Conditions for Clearing the DTC |
The DTCs are Type C DTCs.
| Diagnostic Aids |
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This diagnostic uses a comprehensive approach to the diagnosis of the KR31 auxiliary coolant pump relay and its related circuits. The auxiliary coolant pump relay is a circuit board (PCB) relay. The relay is an integral component to the underhood bussed electrical center (UBEC). It cannot be removed and it is not visible.
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Most of the diagnosis is performed at the ECM connectors. Great care should be taken to ensure that the correct terminals are tested and the proper test probes are utilized when performing this diagnostic.
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The test lamp is used to provide a visual aid to observe the integrity of the KR31 relay, the UBEC and the relay control circuit.
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Grounding terminal X2-58 activates the powertrain relay, which will supply power through KR31 relay coil and the relay control circuit. Under normal circumstances the test lamp will illuminate with dim intensity due to the load created by the KR31 relay coil. If the test lamp does not illuminate, or illuminates brightly a condition exists in the KR31 relay control circuit or the UBEC.
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| Reference Information |
Schematic Reference
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Engine Cooling Schematics
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Engine Controls Schematics (3.0L (LF1))
Engine Controls Schematics (2.8L (LAU))
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Connector End View Reference
Component Connector End Views
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| 1. |
Ignition ON, verify that DTC P0480, P0691, or P0692, is not set.
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| 2. |
If a DTC is set, refer to
DTC P0480, P0691, or P0692 (without/LF1)
for further diagnosis.
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Command the cooling fan ON from 20-90 % with a scan tool. Verify that the cooling fan turns ON and operates as commanded. |
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If the cooling fan does not respond to the commanded states, refer to
Cooling Fan Inoperative (LAU)
Cooling Fan Inoperative (LF1)
for further diagnosis.
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Ignition ON, command the KR31 auxiliary coolant pump relay ON and OFF with the scan tool. An audible click should be heard when changing between the commanded states.
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Start the engine. Check the DTC information with a diagnostic tool. DTC P2600, P2602, or P2603 should not set.
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Ignition ON, engine OFF, check the DTC information with a scan tool. DTC P2601 should not be set.
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| 8. |
If DTC P2601 is set, refer to the following procedures for further diagnosis:
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After Boil Coolant Pump Always On
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After Boil Coolant Pump Inoperative
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After Boil Coolant Pump Malfunction
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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.
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| Circuit/System Testing |
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Warning
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Ignition OFF, disconnect harness connector X2 at the K20 ECM. |
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Connect a test lamp between terminal X2-45 and ground.
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| 3. |
Ignition ON, connect a fused jumper wire between the powertrain relay control circuit terminal X2-58 and ground. The test lamp should illuminate with low intensity. |
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If the test lamp does not illuminate, test the auxiliary coolant pump relay control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the X50A underhood fuse block (UBEC).
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If the test lamp illuminates with bright intensity, test the auxiliary coolant pump relay control circuit for a short to voltage. If the circuit tests normal, test or replace the X50A UBEC.
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If all circuits/connections test normal, replace the K20 ECM.
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| Component Testing |
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Ignition OFF, disconnect and remove the X50A UBEC.
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Remove the KR75 powertrain relay.
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Test for 170-210 Ω between the powertrain relay switched output circuit terminal 87 and the auxiliary coolant pump relay control circuit at UBEC terminal X2-21.
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If not within the specified range, replace the X50A UBEC.
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Test for greater than 2 Ω between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4.
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If less than the specified range, replace the X50A UBEC.
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Connect a 10 A fused jumper wire from the positive terminal of the battery to the powertrain relay switched output circuit terminal 87. Connect a jumper wire from the negative terminal of the battery to the auxiliary coolant pump relay control circuit at UBEC terminal X2-21. Test for less than 2 Ω between UBEC B+ supply cable and the AFTERBOIL PUMP Fuse 4.
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If greater than the specified range, replace the X50A UBEC.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Front Compartment Fuse Block Replacement
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Control Module References
for ECM replacement, setup, and programming
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