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Home >> Lexus >> 2004 >> IS 300 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 57 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input) Or DTC P0850: Park/Neutral Switch Input Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Lexus scan tool can be used to confirm PNP switch signal from CURRENT DATA.
  1. Jack up the vehicle. Disconnect the park/neutral position switch connector. See Fig 1. Check continuity between each terminal when the shift lever is moved to each position. See PARK/NEUTRAL POSITION SWITCH CONTINUITY  table. If continuity is as specified, go to next step. If continuity is not as specified, replace park/neutral position switch.
    Fig 1: Identifying Park/Neutral Position Switch Connector Terminals
    G00239915Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    PARK/NEUTRAL POSITION SWITCH CONTINUITY

    Shift Lever Position Terminal No. To Continuity
    P 1-3, 6-9
    R 2-3
    N 3-5, 6-9
    D, 4 3-7
    3 3-4
    2, L 3-8
  2. Connect park/neutral position switch connector. Disconnect shift lock control computer connector (transmission control switch). See Fig 2. Check continuity between each terminal of shift lock control computer (transmission control switch). See CHECKING SHIFT LOCK CONTROL COMPUTER CONTINUITY  table. If problem exists, replace transmission control switch. If problem does not exist, go to next step.
    Fig 2: Identifying Shift Lock Control Computer Connector Terminals
    G00239916Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    SHIFT LOCK CONTROL COMPUTER CONTINUITY

    Shift Position Tester Connection Specified Value
    D 1-8 (NSSD-AT4) No Continuity
    4 1-8 (NSSD-AT4) Continuity
    2 6-12 (NSSL-ATL) No Continuity
    L 6-12 (NSSL-ATL) Continuity
  3. Reconnect shift lock control unit assembly connector. Disconnect ECM connectors. Turn ignition switch ON and measure voltage between terminals NSW, P, R, N, D, 4, 3, 2, L and E1 of ECM when shift lever is shifted to specified position. See PARK/NEUTRAL POSITION SWITCH/ECM VOLTAGE CHECK  table. If voltage is to specification, replace ECM. If voltage is not to specification, repair or replace harness or connector.
    PARK/NEUTRAL POSITION SWITCH/ECM VOLTAGE CHECK

    Tester Connection Shift Lever Position Specification
    NSW-Ground P & N Less Than One Volt
    NSW-Ground Except P & N Battery Voltage
    P-Ground P-E1 Battery Voltage
    R-Ground N-E1 Battery Voltage (1)
    N-Ground R-E1 Battery Voltage
    D-Ground D-E1 Battery Voltage
    4-Ground 4-E1 Battery Voltage
    3-Ground 3-E1 Battery Voltage
    2-Ground 2-E1 Battery Voltage
    L-Ground L-E1 Battery Voltage
    (1) Voltage will drop slightly due to back-up light operation.
  4. Check wiring between battery and PNP switch and between PNP switch and ECM. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair wiring as necessary.
    Fig 3: Identifying P, R, N, D, 4, 3, 2, L Switch & E1 ECM Connector Terminals
    G00239917Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    Fig 4: Identifying Park/Neutral Position Switch Voltage Specifications
    G00239918Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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