1996 - 2000 Rav4 EGR Diagnosis, Engine Testing, Bench Testing, EGR Valve, Vacuum Modulator, VSV

This video shows the layout, parts, and function of the EGR, or Exhaust Gas Recirculation, system on the '96 - '00 Rav4. The EGR Valve, EGR Vacuum Modulator, and VSV (Vacuum Switching Valve) are shown, testing, and explained. Check the Pinned Comment or the Timestamps below to skip around (links for the EGR Valve and VSV replacement videos are below the Timestamps):

EGR Components Detailed Explanation:
00:01:10 What is EGR (Exhaust Gas Recirculation)
00:01:50 Path of Exhaust Gas from Exhaust Manifold to Intake

00:02:27 EGR Valve location and begin explanation
00:02:28 EGR Pipe location
00:03:08 EGR Valve in hand
00:04:15 EGR pintle when under vacuum
00:06:17 Connection between EGR Valve and Vacuum Modulator
00:06:35 The two "sides" of the EGR circuit (vacuum side and exhaust side)

00:07:13 VSV, Vacuum Switching Valve explanation
00:08:59 VSV with shorter hoses for demonstration
00:11:18 VSV under vacuum, not energized
00:12:37 VSV hooked up to 12v battery for demonstration

00:15:41 Vacuum Modulator explanation
00:16:52 Vacuum Modulator in hand
00:17:43 How to remove Vacuum Modulator
00:18:10 Opening the top of the Vacuum Modulator
00:19:18 Explanation of Q, R, and P ports of Vacuum Modulator

00:22:37 Vacuum sources at Throttle Body
00:23:40 Holes for Ports E and R

00:27:59 Role of ECU (engine computer) in EGR circuit
00:28:49 Role of MAP (Manifold Absolute Pressure) sensor in EGR Circuit

Begin Engine Tests:
00:30:44 Begin In-Engine Tests
00:30:51 Check all vacuum hoses for leaks
00:32:18 Check for vacuum at Throttle Body
00:35:04 Test 1: Check EGR Valve directly to see if it opens
00:39:50 Test 2: Check VSV function with Key OFF and Key ON conditions
00:46:10 Test 3: Check Vacuum Modulator for flow
00:47:59 Test 4: Check Vacuum Modulator for diaphragm response to backpressure
00:50:09 Prepare hose tees and gauges for next tests
00:51:36 Test 5: Check vacuum at Q port
00:59:17 Test 6: Check vacuum at EGR valve with engine cold

Warm up engine before Test 7:
01:01:10 Test 7: Check vacuum at EGR valve with engine warm
01:04:14 Test 8: Check vacuum at Q with full manifold vacuum on P

Bench Tests:
01:11:20 Bench test EGR Valve
01:13:27 Bench test Vacuum Modulator
01:19:42 Bench test VSV

Mini EGR Circuit:
01:25:47 Mini EGR Circuit with no vacuum at R port and some backpressure
01:29:30 Mini EGR Circuit with vacuum at R port and no backpressure

Link for the EGR Valve replacement video:
   • 1996 - 2000 Toyota Rav4 DIY Remove Throttl...  

Link for the VSV Video:
   • 1996 - 2000 Toyota Rav4 EGR VSV, Vacuum Sw...  

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