The Diagnostic Trouble Code (DTC) P0790 signifies a malfunction within the Normal/Performance Switch Circuit in the vehicle’s transmission system. This guide aims to explain the implications of the P0790 code, explore its potential causes, outline associated symptoms, and provide guidance on diagnosing and rectifying issues associated with this specific OBD2 trouble code.

1. What Does P0790 Code Mean?

P0790 specifically identifies an issue within the Normal/Performance Switch Circuit as detected by the vehicle’s Powertrain Control Module (PCM). This code indicates a malfunction in the circuit responsible for controlling the switch between normal and performance transmission modes.

2. What Are The Possible Causes Of P0790 OBD2 Trouble Code?

Several factors might lead to the activation of P0790, including:

• Faulty Switch Circuit: Malfunction or failure within the normal/performance switch circuit.
• Electrical Issues: Wiring harness problems, damaged connectors, or corrosion affecting the circuit’s integrity.
• Defective Switch or Sensor: Issues with the normal/performance switch or associated sensors impacting circuit functionality.
• PCM Malfunction: Anomalies or intermittent problems within the Powertrain Control Module affecting the switch circuit’s operation.

3. What Are The Symptoms Of OBD2 Trouble Code P0790?

When DTC P0790 is active, various symptoms may be observed, including:

• Check Engine Light Activation: Illumination of the check engine light due to detected abnormalities in the switch circuit.
• Transmission Mode Issues: Inability to switch between normal and performance transmission modes.
• Transmission Performance Variation: Irregular performance or operation of the transmission system.
• Reduced Performance: Decreased efficiency or performance during certain driving conditions due to the malfunctioning circuit.

4. How To Diagnose And Repair Problems That Activated DTC P0790 in The PCM?

Accurate diagnosis and repair concerning DTC P0790 involve:

• OBD-II Scan: Employ a diagnostic scanner to retrieve the P0790 code and associated codes for comprehensive analysis.
• Visual Inspection: Inspect the wiring, connectors, and switch for any visible damage, corrosion, or loose connections.
• Circuit Testing: Use a multimeter to test the switch circuit for continuity, shorts, or open circuits, ensuring proper functionality.
• Component Inspection: Assess the switch and related components for potential defects or irregularities impacting circuit operation.
• PCM Assessment: Evaluate the Powertrain Control Module for possible malfunctions affecting the switch circuit.

Conclusion

Understanding DTC P0790 involves recognizing issues within the Normal/Performance Switch Circuit, affecting the transmission’s ability to switch between different modes. Comprehensive diagnosis and repair, including visual inspections, circuit testing, and component assessments, are essential for rectifying this malfunction and ensuring the proper operation of the transmission system.

Consulting certified auto technicians or professionals experienced in transmission repairs is advisable for precise diagnosis and resolution of issues associated with DTC P0790. Timely maintenance and professional guidance significantly contribute to maintaining optimal transmission performance and overall vehicle reliability.