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Home >> Lexus >> 2008 >> IS 250 RWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 22 (Automatic Transaxle) >> Automatic Transmission System >> DTC P2808: Pressure Control Solenoid "G" Performance (Shift Solenoid Valve SL4) >> System Description

System Description

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

Based on signals from the transmission speed sensors (NT, SP2 and NC3), the actual gear is detected. If the detected gear is different than the commanded gear, the TCM detects related mechanical problems in the shift solenoid valves, valve body and automatic transmission.

HINT.

Actual gear when a problem occurs in shift solenoid valve SL4.

SHIFT SOLENOID VALVE REFERENCE

TCM commanded gear 1st 2nd 3rd 4th 5th 6th 7th 8th
Actual gear during SL4 stuck ON malfunction 4th 4th 3rd 4th 6th 6th 7th 6th
Actual gear during SL4 stuck OFF malfunction 1st 2nd 3rd N (1st)(1) 5th N(1) 7th 8th
(1) Neutral
DTC DETECTION CONDITION AND TROUBLE AREA

DTC Code DTC Detection Condition
  1. Diagnosis Condition
  2. Malfunction Status
  3. Malfunction Time
  4. Other
 Trouble Area
P2808
  1. ECT is 40°C (104°F) or more, ATF temperature is -10°C (14°F) or more, and vehicle is driven with shift lever in D (no malfunctions are detected in shift solenoid valve SL1, 2, 3, 4 and 5, SR, speed sensors (NT, NC3, SP2), water temperature sensor, oil temperature sensor, knock control sensor, electronic throttle, or CAN2)
  2. One of following occurs
    1. When gear shifts to 1st are requested by TCM, actual gear changes to 4th gear
    2. When gear shifts to 2nd are requested by TCM, actual gear changes to 4th gear
    3. When gear shifts to 5th are requested by TCM, actual gear changes to 6th gear
    4. When gear shifts to 8th are requested by TCM, actual gear changes to 6th gear
  3. Malfunction status occurs 2 times (1 trip)
  4. 2 trip detection logic
  • Shift solenoid valve SL4
  • Valve body assembly
  • Automatic transmission assembly
P2808
  1. ECT is 40°C (104°F) or more, ATF temperature is -10°C (14°F) or more, and vehicle is driven with shift lever in D (no malfunctions are detected in shift solenoid valve SL1, 2, 3, 4 and 5, SR, speed sensors (NT, NC3, SP2), water temperature sensor, oil temperature sensor, knock control sensor, electronic throttle, or CAN2)
  2. When gear shifts to 4th or 6th are requested by TCM, engine speed overruns (neutral status)
  3. Malfunction status continues for 0 5 sec or more (1 trip)
  4. 2 trip detection logic
  • Shift solenoid valve SL4
  • Shift solenoid valve SLT
  • Valve body assembly
  • Automatic transmission assembly
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