Skip to content
GTECH Calibration
Portal

P1870

Transmission Component Slipping.

  • Saturn
  • Powertrain
  • Manufacturer code
  • High severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
70
FaultThe specific fault in that area

What it means

P1870 on a Saturn means the transmission control module has detected Transmission Component Slipping. It compares engine speed with transmission input and output speed and sees a ratio that does not match the commanded gear, so a clutch, band or the torque converter clutch is not holding properly. The exact component monitored depends on the model and transmission fitted.

Symptoms

  • Engine revs rise without matching acceleration during a gear change
  • Delayed or soft engagement when selecting Drive or Reverse
  • Slipping or flaring between gears, especially under load
  • Transmission stuck in limp mode or a fixed gear
  • Burnt smell from the transmission fluid
  • Check engine light or transmission warning lamp on

Possible causes

  • Low or degraded transmission fluid, or the wrong fluid typelikely
  • Worn clutch packs or bands inside the transmissionlikely
  • Low line pressure from a clogged filter, weak pump or internal leakspossible
  • Faulty shift or pressure control solenoid, or a sticking valve bodypossible
  • Faulty input or output speed sensor giving incorrect readings, or damaged wiring and connectorspossible
  • Torque converter clutch failurepossible
  • Outdated control module software where the manufacturer has issued an updaterare

How to diagnose

  1. Read all stored codes and freeze frame data to see gear, load, speed and temperature when the fault set
  2. Check transmission fluid level, condition and smell, and compare with the specification for the model
  3. Inspect the transmission wiring, connectors and speed sensor plugs for damage, corrosion or fluid contamination
  4. Check for any other transmission or engine codes, and fix misfire or sensor faults first
  5. Watch live data for input speed, output speed and gear ratio during a road test to find which gear slips
  6. Check line pressure with a gauge against the manufacturer's figures for the specific transmission
  7. Test the shift and pressure solenoids electrically and check for sticking in the valve body
  8. Check for any technical service bulletins or software updates for the model and transmission

How to fix

  • Correct the fluid level, or replace degraded fluid and filter with the specified type
  • Repair or replace damaged wiring, connectors or faulty speed sensors
  • Replace faulty solenoids or repair the valve body
  • Replace or repair the torque converter if its clutch is slipping
  • Overhaul or replace the transmission if clutches, bands or the pump are worn
  • Apply a manufacturer calibration update if an outdated one is a known cause for that model

Can I keep driving?

High severity

Limit driving and avoid heavy loads, as continued slipping quickly burns clutches and can destroy the transmission. Have it checked as soon as possible, and do not tow or drive far if it is slipping badly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

Nearby codes