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• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Relay Coil Ignition | P0691 00, P0693 00 | P0691 00, P0693 00 | - | - |
Relay Switch B+ | 1 | 1 | - | - |
Relay Control | P0693 00 | P0693 00 | P0694 00 | - |
Relay Controlled Output Control | 2 | 2 | 3 | - |
1. Low and medium speed fan inoperative without a DTC. 2. Medium speed fan inoperative without a DTC. 3. Medium speed fan always ON without a DTC. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Relay Coil Ignition | P0691 00, P0693 00 | P0691 00, P0693 00 | - | - |
Relay Switch B+ | 1 | 2 | - | - |
Relay Control | 3 | 4 | - | - |
Relay Controlled Output Control | 2 | 2 | 3 | - |
1. Low and medium speed fan inoperative without a DTC. 2. Low speed fan inoperative without a DTC. 3. Low speed fan always ON without a DTC. 4. Low and high speed fan inoperative without a DTC. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Relay Coil Ignition | P0693 00 | P0693 00 | P0693 00 | - | - |
Relay Switch B+ | 2 | 2 | 2 | - | - |
Relay Control | P0693 00 | 2 | P0693 00 | 1 | - |
Relay Controlled Output Control | P0693 00 | 2 | P0693 00 | 3 | - |
1. Medium speed fan replaced by high speed fan without a DTC. 2. High speed fan inoperative without a DTC. 3. High speed fan always ON without a DTC. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Relay Coil Ignition | P0691 00, P0693 00 | 1 | 1 | - | - |
Relay Switch Ignition | P0693 00 | 1 | P0693 00 | - | - |
Relay Control | 2 | 1 | 1 | - | - |
Relay Controlled Output Control | P0693 00 | 1 | P0693 00 | 3 | - |
1. High speed fan inoperative without a DTC. 2. Low speed fan always ON without a DTC. 3. Medium speed fan replaced by high speed fan without a DTC. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Relay Coil Ignition | P0691 00, P0693 00 | 3 | P0691 00, P0693 00 | - | - |
Relay Control | P0691 00 | 1 | P0691 00 | P0692 00 | - |
Relay Controlled Output Control | - | 1 | 1 | 1 | - |
Relay Switch Ground | 2 | 3 | 3 | 3 | - |
1. Low speed fan inoperative without a DTC. 2. Low speed fan always ON without a DTC. 3. Low and high speed fan inoperative without a DTC. |
The engine control module (ECM) commands the fan ON in either high speed, medium speed, or low speed, depending on cooling requirements. In low speed, the fan is turned ON at a reduced speed. In medium speed, the fan is turned ON at a higher reduced speed. In high speed, the fan is turned ON at full speed. In low speed operation, the ECM provides ground to ECM terminal 51 X1. The cooling fan relay activates and provides ground to the coils of the cooling fan medium speed 2 relay and the cooling fan speed control relay. The cooling fan speed control relay activates and provides power to the coil of the cooling fan high speed relay. The cooling fan high speed relay remains inactive because ECM terminal 71 X2 is not grounded. The cooling fan medium speed 2 relay provides power to the engine cooling fan motor through cooling fan terminal 3 and the internal fan resistor. In medium speed operation, the ECM provides ground to ECM terminal 71 X2. The cooling fan high speed relay remains inactive because power is not provided to the coil from the cooling fan speed control relay. The cooling fan medium speed 1 relay activates and provides power to the engine cooling fan motor through cooling fan terminal 2 and the internal fan resistor. In high speed operation, the ECM provides ground to ECM terminals 51 X1 and 71 X2. As previously described, power is now provided to both cooling fan terminals 2 and 3. In addition, power and ground are now provided to the coil of the cooling fan high speed relay. The cooling fan high speed relay activates and provides power to the engine cooling fan motor through cooling fan terminal 4, bypassing the resistors.
• | The ignition voltage is between 8-18 V. |
• | The engine is running greater than or equal to 400 RPM. |
The ECM detects a short to ground or open circuit on the cooling fan relay control circuit for more than 1 s.
The ECM detects a short to voltage on the cooling fan relay control circuit for more than 1 s.
The ECM detects a short to ground or open circuit on the cooling fan high speed relay control circuit for more than 1 s.
The ECM detects a short to voltage on the cooling fan high speed relay control circuit for more than 1 s.
DTCs P0691 00, P0692 00, P0693 00 and P0694 00 are Type B DTCs.
DTCs P0691 00, P0692 00, P0693 00 and P0694 00 are Type B DTCs.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If the fan does not operate correctly, refer to Low Speed Malfunction. |
⇒ | If the fan does not operate correctly, refer to Medium Speed Malfunction. |
⇒ | If the fan does not operate correctly, refer to High Speed Malfunction. |
Note: Circuit/System Verification must be performed before Circuit/System Testing.
• | KR20B Cooling Fan Medium Speed 2 Relay |
• | KR20E Cooling Fan Speed Control Relay |
• | KR20F Cooling Fan Relay |
• | KR20B Cooling Fan Medium Speed 2 Relay terminal 87 |
• | KR20E Cooling Fan Speed Control Relay terminal 87 |
⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
⇒ | If greater than the specified range, test the output circuit for an open/high resistance. |
• | KR20B Cooling Fan Medium Speed 2 Relay terminal 86 |
• | KR20F Cooling Fan Relay terminal 86 |
⇒ | If the test lamp does not illuminate, test the relay coil 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 the relay switch controlled output circuit terminal 87 at the KR20E Cooling Fan Speed Control Relay connector for a short to ground. If the circuit tests normal, test or replace the KR20E Cooling Fan Speed Control Relay. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit terminal at the relay connectors listed below for a short to ground: |
• | KR20B Cooling Fan Medium Speed 2 Relay terminal 87 |
• | KR20A Cooling Fan Medium Speed 1 Relay terminal 30 |
⇒ | If the test lamp does not illuminate, test the relay switch ignition circuit terminal 30 at the KR20F Cooling Fan Relay connector for an open/high resistance. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the cooling fan does not activate at low speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan. |
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp does not turn OFF, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp does not turn ON, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
• | KR20B Cooling Fan Medium Speed 2 Relay |
• | KR20F Cooling Fan Relay |
⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, test the KR20E Cooling Fan Speed Control Relay for correct operation. If the relay tests normal, replace the K20 Engine Control Module. |
⇒ | If the cooling fan does not activate, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
⇒ | If the test lamp does not turn OFF, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp does not turn ON, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
• | KR20D Cooling Fan High Speed Relay |
• | KR20E Cooling Fan Speed Control Relay |
⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ignition circuit terminal 86 of the KR20D Cooling Fan High Speed Relay connector for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
⇒ | If the cooling fan does not activate at high speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
⇒ | If the test lamp does not turn ON, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
• | KR20D Cooling Fan High Speed Relay |
• | KR20E Cooling Fan Speed Control Relay |
⇒ | If not within the specified range, replace the relay. |
• | 30 and 85 |
• | 30 and 86 |
• | 30 and 87 |
• | 85 and 87 |
⇒ | If less than the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Engine Control Module Replacement : 1.6L LDE, LXV, 1.8L 2H0, LFH, and LUW for ECM replacement, setup, and programming
© Copyright Chevrolet. All rights reserved |
© Copyright Chevrolet. All rights reserved |