Failed pulse generator (speed sensor) assembly inside the transmission; Damaged or corroded wiring harness connector at the sensor; Open or short circuit in the signal or ground wire between sensor and TCM; Metal debris or sludge buildup on the sensor tip, blocking the magnetic pickup; Internal transmission mechanical damage affecting the reluctor wheel or tone ring; Faulty TCM (less common, but possible after other causes are ruled out)

DTC codes / Mitsubishi codes / P1715

P1715 · MitsubishiPulse Generator Assembly

Q: What does code P1715 mean?

Pulse Generator Assembly. P1715 on Mitsubishi vehicles indicates that the Transmission Control Module (TCM) has detected an abnormal signal from the pulse generator assembly, which is the input or output speed sensor inside the transmission. The TCM uses these pulses to calculate gear ratios and control shift timing, so when the signal is missing or erratic, the computer flags the circuit.

P1715 on Mitsubishi vehicles indicates that the Transmission Control Module (TCM) has detected an abnormal signal from the pulse generator assembly, which is the input or output speed sensor inside the transmission. The TCM uses these pulses to calculate gear ratios and control shift timing, so when the signal is missing or erratic, the computer flags the circuit.

SystemPowertrain

Code typeMitsubishi specific

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Symptoms you may notice

Check Engine Light or Transmission Warning Light illuminated on the dashboard
Harsh or delayed shifting, often with a default to a single gear (limp mode)
Speedometer fluctuation or failure if the affected sensor drives the speedometer signal
Transmission may not downshift properly when coming to a stop
Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

Failed pulse generator (speed sensor) assembly inside the transmission
Damaged or corroded wiring harness connector at the sensor
Open or short circuit in the signal or ground wire between sensor and TCM
Metal debris or sludge buildup on the sensor tip, blocking the magnetic pickup
Internal transmission mechanical damage affecting the reluctor wheel or tone ring
Faulty TCM (less common, but possible after other causes are ruled out)

How to diagnose and fix it

Scan all modules for stored and pending codes, and record freeze-frame data to confirm when the fault occurs
Visually inspect the pulse generator connector and wiring for corrosion, chafing, or loose pins
Measure the sensor resistance and compare to the manufacturer's specification; replace if out of range
Check the sensor signal with an oscilloscope or a scan tool that can graph input speed while driving
Remove the sensor and inspect the tip for metal shavings or damage; clean or replace as needed
Check the transmission fluid level and condition; contaminated fluid can affect sensor operation
If the circuit and sensor test good, perform a continuity and short-to-ground test on the signal wires back to the TCM

What Mitsubishi techs check before replacing the sensor

A common oversight is assuming the sensor is bad when the real problem is a worn tone ring or reluctor wheel inside the transmission, which produces an erratic signal that mimics a faulty sensor.
Intermittent P1715 codes often trace to a chafed wire near the transmission mount or a connector that wicks moisture, so wiggle-testing the harness while watching live data is more reliable than a static resistance check.
On some Mitsubishi models, the pulse generator assembly shares a ground with other sensors, and a bad ground can set P1715 along with other codes; always check grounds before condemning the sensor.
Debris on the sensor tip from normal clutch or gear wear can cause a weak signal without any mechanical failure, so cleaning the sensor and clearing the code is a valid first step before replacement.
A failing TCM can intermittently drop the sensor signal, but this is rare; rule out all wiring and sensor issues first to avoid an expensive misdiagnosis.

Can I keep driving with P1715?

You can usually drive the vehicle to a repair shop, but expect harsh shifting or limp mode and avoid sustained highway speeds or heavy loads until the fault is repaired. If the transmission is stuck in a single gear or the speedometer has failed, limit driving to short, low-speed trips.

Tools that help

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Guidance is general and written for Mitsubishi vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.