For 1990-2009 cars only
Diagnostic Instructions
| • | 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. |
DTC Descriptor
DTC P0027: Exhaust Throttle Control Valve PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Exhaust Brake and Exhaust Throttle Solenoid Control Circuit | P0079 | P0079 | P0080 |
Circuit/System Description
The exhaust throttle solenoid is installed to the frame near the exhaust throttle valve of the exhaust pipe. When the diesel particulate filter (DPF) regeneration mode is ON and the exhaust brake is ON , then the exhaust throttle solenoid is turned ON by the engine control module (ECM). The ECM detects an open or closed position of a valve from the mass air flow (MAF) value and an engine speed.
Conditions for Running the DTC
| • | DTCs P0079, P0080, P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0126, P0201, P0202, P0203, P0204, P0205, P0206, P02E7, P02E8, P0335, P0336, P0403, P0404, P0409, P0506, P0507, P0602, P0652, P0653, P1125, P1293, P2002, P2100, P2146, P2147, P2148, P2149, P2150, P2151, P2161, P2164, P2167, P2170, P2173, P2176, P2227, P2228, P2229, P2454, and P268A are not set. |
| • | The battery voltage is between 10-16 volts. |
| • | The engine is running for longer than 5 seconds. |
| • | The engine speed is between 450-1,000 RPM. |
| • | The engine coolant temperature (ECT) is between 60-90°C (140-194°F). |
| • | The intake air temperature (IAT) is between -10 and +119°C (+14 and +246°F). |
| • | The barometric pressure (BARO) is more than 75 kPa. |
| • | The accelerator pedal position is less than 3 percent. |
| • | The vehicle speed is less than 3 km/h (2 mph). |
| • | The DPF differential pressure is between -10 and +20 kPa. |
| • | The exhaust brake command is OFF. |
| • | The exhaust throttle command is ON. |
| • | The power take-off (PTO) control is not active. |
Conditions for Setting the DTC
| • | The ECM detects that the exhaust throttle systems closed stuck condition or open stuck condition. |
| • | The main input is the engine speed and the MAF value. |
Action Taken When the DTC Sets
DTC P0027 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0027 is a Type A DTC.
Diagnostic Aids
Inspect for any recent engine mechanical repairs. An incorrectly installed exhaust throttle solenoid exhaust throttle will cause this DTC to set.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| • | If DTC P0079, P0080, P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0126, P0201, P0202, P0203, P0204, P0205, P0206, P02E7, P02E8, P0335, P0336, P0403, P0404, P0409, P0506, P0507, P0602, P0652, P0653, P1125, P1293, P2002, P2100, P2146, P2147, P2148, P2149, P2150, P2151, P2161, P2164, P2167, P2170, P2173, P2176, P2227, P2228, P2229, P2454 and P268A are set, test and repair those DTCs first. |
| • | Verify the integrity of the air induction system by inspecting for the following conditions: |
| - | Damaged components |
| - | Restrictions in the MAF air induction system |
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, disconnect the harness connector at the mass air flow (MAF) sensor.
- Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 4 and ground.
- Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and ground.
- Verify the scan tool MAF parameter is less than 1 g/s.
- Install a 3A fused jumper wire between the signal circuit terminal 5 and the ignition circuit terminal 3. Verify the scan tool MAF parameter is more than 500 g/s.
- If all circuits test normal, replace the MAF sensor.
- Ignition OFF, disconnect the harness connector at the exhaust throttle solenoid.
- Ignition ON, verify that a test lamp illuminates between the power supply circuit and ground.
- Ignition OFF, disconnect the harness connector at the ECM.
- Install a 3A fused jumper wire between the power supply circuit and the control circuit at the exhaust throttle solenoid.
- Ignition ON, verify that a test lamp illuminates between the control circuit at ECM and ground.
- Ignition OFF, test for 15-20 ohms at the solenoid terminal.
- Inspect the exhaust throttle.
| ⇒ | If greater than 5 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
| ⇒ | If greater than 1 g/s, test the signal circuit terminal 5 for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than 500 g/s, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If the test lamp does not illuminate, test the power supply circuit for a short to ground or an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the power supply circuit for a short to ground or an open/high resistance. |
| ⇒ | If not within 15-20 ohms, replace the solenoid. If the solenoid tests normal, replace the ECM. |
| ⇒ | If abnormal condition detected, replace the exhaust throttle. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
