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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 125 (Engine Control System Self Diagnostics (2UZ-FE)) >> Diagnostic Tests >> DTC P0451, DTC P0452 &/Or DTC P0453 >> Diagnosis & Repair

Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove glove box for access to ECM with electrical connectors still installed on ECM. See Figure. Turn ignition on. Using voltmeter, check voltage between ECM 34-pin connector E4 terminals No. 18 (+) (Black/Red wire) and No. 28 (-) (Brown wire). See Figure. This is the VC+ and E2- terminals on ECM. Voltage should be 4.5-5.5 volts. If voltage is within specification, go to next step. If voltage is not within specification, replace ECM.
  2. Turn ignition off. Backprobing, connect voltmeter between ECM 31-pin connector E8 terminal No. 21 (Orange wire) and ECM 34-pin connector E4 terminal No. 28 (Brown wire). See Figure. This is the E2 and PTNK terminals on ECM. Disconnect vacuum hose from vapor pressure sensor. Turn ignition on and note voltage. Voltage should be 2.9-3.7 volts. Turn ignition off. Then, connect vacuum/pressure pump to vapor pressure sensor vacuum port. Apply 1.18 in. Hg vacuum to sensor. Turn ignition on and measure voltage. Voltage should be less than 0.5 volt. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM.
  3. Turn ignition off. Disconnect vapor pressure sensor 3-pin connector and ECM 31-pin connector E8 and ECM 34-pin connector E4. Vapor pressure sensor is located on top of fuel pump assembly on top of fuel tank and contains a 3-pin electrical connector with Black/Red, Orange and Brown wires. See Fig 1, Fig 2 and Fig 3 . Check continuity between ECM E4 connector terminal No. 28 and VPS 3-pin connector terminal No. 1, between ECM E8 connector terminal No. 21 and VPS 3-pin connector terminal No. 2, and between ECM E4 connector terminal No. 18 and VPS 3-pin connector terminal No. 3. Continuity should exist at all 3 checks. Then, check that continuity does not exist between ground and VPS 3-pin connector terminals No. 2 and 3 individually. If continuity is as specified, replace vapor pressure sensor. See VAPOR PRESSURE SENSOR under EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. If continuity is not as specified, repair or replace wires and/or connectors as necessary.
Fig 1: Locating EVAP Emission Control System Components (1 Of 2)
G00232575Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 2: Locating EVAP Emission Control System Components (2 Of 2)
G00232576Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 3: Identifying Vapor Pressure Sensor (VPS) Connector & Terminals
G00232580Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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