Archives: DTC Codes

What Does Code P1642 Mean? DTC P1642 signifies an issue within the fuel pump monitor circuit, specifically indicating a “High Input” condition detected by the Powertrain Control Module (PCM) or Engine Control Module (ECM). The PCM utilizes a dedicated feedback circuit to monitor the operational status and integrity of the fuel pump and its associated […]

What Does Code P1643 Mean? DTC P1643 signifies a “Fuel Pump Monitor Circuit Low Input.” This code indicates that the Powertrain Control Module (PCM), or Engine Control Module (ECM) depending on the manufacturer, has detected a voltage signal from the fuel pump monitor circuit that is below its calibrated operational threshold. Modern fuel delivery systems […]

What Does Code P1644 Mean? DTC P1644 signifies a detected malfunction within the fuel pump speed control circuit. In modern fuel systems, the Powertrain Control Module (PCM), also referred to as the Engine Control Module (ECM), does not directly power the fuel pump at a constant voltage. Instead, it communicates with a dedicated Fuel Pump […]

What Does Code P1645 Mean? The diagnostic trouble code P1645, defined as “Fuel Pump Resistor Switch Circuit Malfunction,” indicates that the Engine Control Module (ECM), also commonly referred to as the Powertrain Control Module (PCM), has detected an electrical fault within the circuit responsible for controlling the fuel pump’s speed or output via a series […]

What Does Code P1650 Mean? The OBD-II diagnostic trouble code P1650, “PSP Switch Out of Self Test Range,” indicates that the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected an illogical or out-of-specification signal from the Power Steering Pressure (PSP) switch during its diagnostic self-test routine. The PSP switch is an integral […]

What Does Code P1651 Mean? The diagnostic trouble code P1651, typically a manufacturer-specific code often seen in Ford vehicles, indicates a malfunction within the Power Steering Pressure (PSP) switch input circuit. The Powertrain Control Module (PCM) or Engine Control Module (ECM) monitors the signal from the PSP switch to detect periods of high parasitic load […]

What Does Code P1652 Mean? DTC P1652 signifies “IAC Monitor Disabled by PSP Switch Failed On,” indicating a specific issue with the Powertrain Control Module (PCM or ECM)’s ability to properly monitor and control idle speed. The Idle Air Control (IAC) system, or in newer vehicles, the electronic throttle body (ETB) which performs similar functions, […]

What Does Code P1653 Mean? The OBD-II diagnostic trouble code P1653 typically indicates a malfunction within the Power Steering Output Circuit. This is often a manufacturer-specific code, commonly observed in Honda/Acura vehicles, but conceptually applies to any system where the Powertrain Control Module (PCM) or Engine Control Module (ECM) directly monitors or controls aspects of […]

What Does Code P1654 Mean? The diagnostic trouble code P1654, defined as “Recirculation Override Circuit Malfunction,” indicates that the Engine Control Module (ECM), often referred to as the Powertrain Control Module (PCM), has detected an electrical anomaly within the control circuit for a recirculation system. While the specific application can vary slightly by manufacturer, P1654 […]

What Does Code P1655 Mean? DTC P1655 is a manufacturer-specific diagnostic trouble code indicating a malfunction within the Starter Disable Control Circuit. This code is set by the Powertrain Control Module (PCM), also referred to as the Engine Control Module (ECM), when it detects an unexpected electrical state or an implausible signal in the circuit […]