P166A

DTC P166A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach. Initial Inspection and Diagnostic Overview
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P166A

Exhaust Control Valve Control Circuit

Diagnostic Fault Information





Circuit/System Description

Exhaust tail pipe flow valve control module receives throttle position sensor and RPM information via serial data from powertrain control module (PCM). The exhaust tail pipe flow valve control module uses this information to determine if to command exhaust tail pipe flow control valve solenoid ON or OFF. When commanded OFF the exhaust tail pipe flow control valve solenoid allows vacuum to flow to close exhaust valve.

Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is greater than 8 volts.

Conditions for Setting the DTC

* Exhaust tail pipe flow valve control module detects short to voltage on exhaust valve solenoid supply voltage circuit.
* Exhaust tail pipe flow valve control module detects short to ground on exhaust valve solenoid supply voltage circuit.

Action Taken When the DTC Sets

Exhaust flow control valve defaults to open.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.

Reference Information

Schematic Reference

Exhaust System Schematics

Connector End View Reference

Exhaust System Connector End Views

Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

Scan Tool Data List for exhaust tail pipe flow valve control module

Circuit/System Testing

1. Ignition OFF, disconnect the exhaust tail pipe flow control valve solenoid connector.
2. Ignition ON, measure for 0 volts between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground.
^ If over 0 volts, test for short to voltage in exhaust valve solenoid supply voltage circuit.

3. Ignition ON, use scan tool to command exhaust flow control relay ON, measure for 10 volts or above between the exhaust tail pipe flow control valve solenoid supply voltage circuit and ground.
^ If under 10 volts, test for short to ground in exhaust valve solenoid supply voltage circuit.

4. If all circuits test normal replace the exhaust tail pipe flow valve control module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Programing and Relearning, Programming and Relearning