Archives: DTC Codes

What Does Code P1720 Mean? DTC P1720 indicates a detected malfunction within the vehicle speed (meter) circuit. The Engine Control Module (ECM), often referred to as the Powertrain Control Module (PCM), monitors the electrical signal generated by the Vehicle Speed Sensor (VSS) to determine the vehicle’s road speed. This signal is critical for a multitude […]

What Does Code P1721 Mean? The diagnostic trouble code P1721 signifies an “Incorrect Ratio” detected for Gear 1 within the automatic transmission system. This code is primarily set by the Transmission Control Module (TCM), or in some integrated systems, the Powertrain Control Module (PCM). The module constantly monitors the rotational speed of the transmission’s input […]

What Does Code P1722 Mean? DTC P1722 signifies “Gear 2 Incorrect Ratio.” This code is set by the Powertrain Control Module (PCM) or Transmission Control Module (TCM) when it detects a discrepancy between the expected gear ratio for 2nd gear and the actual observed gear ratio. The PCM/TCM continuously monitors the transmission input shaft speed […]

What Does Code P1723 Mean? DTC P1723, “Gear 3 Incorrect Ratio,” indicates that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected a discrepancy in the calculated gear ratio when the transmission is commanded to operate in 3rd gear. Modern automatic transmissions utilize input shaft speed (ISS) and output shaft speed (OSS) […]

What Does Code P1724 Mean? DTC P1724 signifies “Gear 4 Incorrect Ratio” within the automatic transmission system. This code is set by the Powertrain Control Module (PCM) or Transmission Control Module (TCM) when it detects a significant deviation between the actual gear ratio and the expected gear ratio for 4th gear. The PCM/TCM continuously monitors […]

What Does Code P1725 Mean? The diagnostic trouble code P1725, “Insufficient Engine Speed Increase During Self Test,” indicates that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected an anomaly during a pre-programmed diagnostic routine. Specifically, during a self-test designed to evaluate the operational integrity of the transmission system (often involving the […]

What Does Code P1726 Mean? DTC P1726 signifies “Insufficient Engine Speed Decrease During Self Test,” a manufacturer-specific code predominantly found in Ford vehicles. This code is typically set when the Powertrain Control Module (PCM), also known as the Engine Control Module (ECM), performs a Key On Engine Running (KOER) self-test. During specific stages of this […]

What Does Code P1727 Mean? DTC P1727 signifies an “Inductive Signature Malfunction” specifically related to the Coast Clutch Solenoid. The Powertrain Control Module (PCM), or in some applications, the dedicated Transmission Control Module (TCM), continuously monitors the electrical characteristics of various solenoids within the automatic transmission. This monitoring includes assessing the solenoid’s resistance, inductance, and […]

What Does Code P1728 Mean? DTC P1728, often described as a “Transmission Slip Error,” signifies that the Powertrain Control Module (PCM) or Transmission Control Module (TCM) has detected an abnormal or excessive slip condition within the automatic transmission. This is typically a manufacturer-specific code, commonly associated with Ford, Mazda, and Mercury vehicles, although its definition […]

What Does Code P1729 Mean? DTC P1729 signifies a detected malfunction within the 4×4 Low range switch circuit. The Powertrain Control Module (PCM), or more commonly, the Transfer Case Control Module (TCCM), monitors the electrical signal from the 4×4 Low range switch, which is typically mounted directly on the transfer case. This switch provides input […]