Archives: DTC Codes

What Does Code P1813 Mean? DTC P1813 signifies a detected open circuit within the transmission’s 4-wheel drive (4WD) mode select system. This fault indicates that the Powertrain Control Module (PCM), or more commonly, the dedicated Transfer Case Control Module (TCCM) or 4×4 Control Module (4x4CM), is not receiving the expected electrical signal from the driver-operated […]

What Does Code P1814 Mean? DTC P1814 indicates a detected Short Circuit To Battery within the 4-Wheel Drive Mode Select circuit. Specifically, the Powertrain Control Module (PCM), or more commonly, the dedicated Transfer Case Control Module (TCCM), has identified an unexpected high voltage condition on the input line responsible for interpreting the driver’s desired 4WD […]

What Does Code P1815 Mean? DTC P1815 indicates that the Powertrain Control Module (PCM), or in some architectures, a dedicated 4-Wheel Drive Control Module (4WDCM) or Transfer Case Control Module (TCCM), has detected a short circuit to ground in the circuit for the 4-Wheel Drive (4WD) Mode Select Switch. This switch is responsible for allowing […]

What Does Code P1816 Mean? The diagnostic trouble code P1816 indicates a malfunction within the Transmission Neutral Safety Switch (NSS) circuit. This switch, often integrated into a Park/Neutral Position (PNP) switch assembly, serves as a critical safety interlock, preventing the engine from starting unless the transmission is securely in either Park (P) or Neutral (N). […]

What Does Code P1817 Mean? DTC P1817 signifies a detected “Open Circuit” condition within the Transmission Neutral Safety Switch (NSS) or its associated electrical circuit. The Powertrain Control Module (PCM), or in some architectures, the Transmission Control Module (TCM), monitors the state of this critical switch. The NSS, often referred to as a Park/Neutral Position […]

What Does Code P1818 Mean? DTC P1818 indicates a “Transmission Neutral Safety Switch Short Circuit To Battery.” This diagnostic trouble code signifies that the Powertrain Control Module (PCM), or in some applications, the Transmission Control Module (TCM), has detected an unintended or continuous high voltage signal on the circuit for the Neutral Safety Switch (NSS). […]

What Does Code P1819 Mean? DTC P1819 signifies that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected a short circuit to ground within the circuit for the Transmission Neutral Safety Switch (NSS), which is often integrated into the Transmission Range Sensor (TRS). The NSS/TRS is a critical component responsible for informing […]

What Does Code P1820 Mean? DTC P1820 signifies a detected electrical malfunction within the Transmission Transfer Case Clockwise Shift Relay Coil Circuit. In vehicles equipped with an electronically controlled transfer case, the transfer case control module (TCCM) or powertrain control module (PCM) monitors the operational status and electrical integrity of the components responsible for shifting […]

What Does Code P1821 Mean? DTC P1821 indicates an “Open Circuit” within the electrical winding of the clockwise shift relay coil responsible for controlling the transfer case’s shifting mechanism. In modern four-wheel-drive (4WD) and all-wheel-drive (AWD) systems, the transfer case typically employs an electric shift motor or actuator to engage various drive modes (e.g., 2WD, […]

What Does Code P1822 Mean? DTC P1822 indicates a detected Short Circuit To Battery within the control circuit for the Transmission Transfer Case Clockwise Shift Relay Coil. In four-wheel drive (4WD) or all-wheel drive (AWD) vehicles, the transfer case is responsible for distributing power from the transmission to both the front and rear axles, enabling […]