Follow us on Twitter


See us on Yelp!



Transmission Information

    If your mechanic tells you ........ you need a new transmission

You need to ask yourself: Did they scan your TCM for DTC’s ?

Did you know that on computer controlled vehicles a minor problem can feel like a major one. Especially with codes MLPS, TPS, or VSS. Even a PCM or PROM or a faulty charging system cam make your vehicle feel like it needs a new transmission and these are external fixes, internal fixes that are sometimes minor repairs that could be a TCCS, EPC, or OOS.

Sounds confusing doesn’t it ?

Here are a list of common transmission terms and abbreviations:

  • DTC’s - Diagnostic Trouble Codes (Information that the computer gives you about a problem you have)
  • EXTERNAL items:
    • Fancy names for neutral safety switches
      • MLPS - Manual lever position switch
        • Without it the computer doesn’t know what gear you have selected
      • PNP - Park / Neutral switch -same as MLPS
      • TRS - Transmision range selector - same as MLPS
    • Fancy names for accelerator lever
      • TPS - Throttle position sendor
        • This tells the computer how much gas you a applying. It also controls passing gear selection.
      • TPP - Throttle position potentiometer - same as TPS
      • FIPL - Fuel injection pump lever - same as TPS
      • DBW - Drive by wire - same as TPS only fully electronic
    • Fancy names for speedometer
      • VSS - vehicle speed sensors
        • This tells tells the computer how fast you are going so it knows when to shift
      • TSS - Turbine speed sensor - same as VSS
      • OSS - Output shaft speed - same as VSS
      • ISS - Input speed sensor
        • This tells the computer how fast the transmission is spinning.
      • PSOM - Programmable speedometer odometer module
        • This tells the computer speed with a tamper proof odometer readout.
    • Fancy names for the computer
      • PCM - Powertrain control module
        • This computer can control motor and transmission
      • TCM - Transmission control module
        • This is the transmission computer
      • VCM - Vehicle control module - same as PCM
      • ECM - Engine control module
        • This is usually engine control only
      • TTVA - Transmission throttle valve actuator
        • Tells the transmission how you are pressing on the throttle
      • PROM - Programmable Read Only Memory
        • This is the computer chip that goes into a PCM that contains the manufacturer’s engine and transmission settings for your specific vehicle’s options and features.
  • INTERNAL items:
    • EPC - Electronic pressure control
      • This controls shift feel in all ranges
    • TCCS - Torque converter clutch solenoid
      • This controls clutch activation (“lockup”)
    • TFT - Transmission fluid temperature
      • This usually means transmission has overheated
    • TOT - Transmission oil temperature - same as TFT
    • PCS - Pressure control solenoid - same as EPC
    • SS1-5 / SSA-E - Shift solenoid
      • This tells you that there is a fault on a specific solenoid
All of the above items control shift strategy
  • OTHER:
    • EGR - Exhaust gas re-circulation
      • Emission fault
    • SRS - Supplemental restraint system
      • Air bag
    • RABS - Rear wheel antilock brake system
      • Brake fault
    • SES - Service engine soon
      • Maintenance required indicator

Serviced brands

Copyright © 2004 by Hi-Tech Transmissions, Inc. All product names and company  logos are the property of their respective owners.