Engine Controls - System/component Tests - 3.2L: Other Honda Passport I

Ground Circuits

Using a DVOM, touch negative voltmeter lead to a good ground. Touch positive voltmeter lead to each ground terminal. With vehicle running, voltmeter should indicate less than one volt. If reading is greater than one volt, check for open, corrosion and loose connection on ground lead. See ECM GROUND LOCATION for ECM ground location.

ECM GROUND LOCATION

Power Circuits (Constant Voltage)

1. ECM should always have constant battery voltage to retain memory.
2. Check voltage at Red/White wires of 24-pin and 32-pin ECM connectors. Voltage is supplied by ECM fuse, located in fuse/relay box at right side of engine compartment.

Power Circuits (Ignition Voltage)

1. ECM should always have battery voltage when ignition is on.
2. Check voltage at Red/Green wire of 24-pin ECM connector. Voltage is supplied by main relay, located on right side of engine compartment. Red/White wire at main relay should have constant battery voltage and Black/Yellow or White/Yellow wire should have voltage only if ignition is on. Voltage to Red/White wire is supplied by Black fusible link, located in fusible link box at right front corner of engine compartment. Black/Yellow or White/Yellow wire receives voltage from fuse No. 8, located in fuse block on left side under dash.

A/C SWITCH

See A/C CLUTCH CONTROL under MISCELLANEOUS CONTROLS.

AIRFLOW SENSOR

Note. Airflow sensor malfunctions may set Code 61 or 62. For additional information, see TESTS W/CODES - 3.2L article.

COOLANT TEMPERATURE SENSOR

Note. Coolant temperature sensor malfunctions may set Code 14A or 14B. For additional information, see TESTS W/CODES - 3.2L article.

1. Unplug coolant temperature sensor.
2. Sensor is located on rear of engine, in coolant transfer tube. Sensor connector contains Gray and Gray/Black wires.
3. Check resistance between sensor terminals at specified temperature. See «COOLANT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-15977-S24996003772000122900000) . Replace sensor if it is not within specification.

COOLANT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

CRANKSHAFT POSITION SENSOR

Note. Crankshaft position sensor malfunctions may set Code 41. For additional testing, see TESTS W/CODES - 3.2L article.

1. Crankshaft position sensor is located on lower right side of engine block, above oil pan. For testing, disconnect crankshaft position sensor connector at DIS module. Using DVOM, probe terminals B1 and B3. Resistance should be 900-1200 ohms.
2. If resistance is as specified, go to next step. If resistance is not as specified, check wiring to sensor for open or shorts and repair as necessary. If wiring is okay, replace sensor.
3. With DVOM connected as in step 1), set DVOM to 2-volt AC scale and crank engine. Ensure reading is greater than .1 volt.

KNOCK SENSOR

See TIMING CONTROL SYSTEMS under IGNITION SYSTEM.

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

Note. A malfunctioning MAP sensor may set Code 33A or 33B. For additional testing, see TESTS W/CODES - 3.2L article.

1. Using Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, connect DVOM (on voltmeter scale) to Green/Orange wire and Blue/White wire at back of MAP sensor connector. Voltage should indicate more than 2.5 volts. Unplug and reconnect MAP sensor vacuum hose. Voltage should indicate less than 2.5 volts. If voltage is not as indicated, replace MAP sensor.
2. Sensor is located on top right side of engine. To diagnose MAP sensor, proceed to «CHART C-1D»(ref-15977-S40535256952000122900000) under DIAGNOSTIC CHARTS.

MANIFOLD AIR TEMPERATURE (MAT) SENSOR

Note. Malfunctioning MAT sensor may set Code 23A or 23B. For additional testing, see TESTS W/CODES - 3.2L article.

1. Remove MAT sensor from intake manifold. MAT sensor is located near throttle position sensor and contains a Blue/Black and Black/White wire connector.
2. Using ohmmeter, check resistance across sensor terminals. Reading should vary with temperature. Replace sensor if not within specification. See «MAT SENSOR RESISTANCE SPECIFICATIONS»(ref-15977-S02906493042000122900000) .

MAT SENSOR RESISTANCE SPECIFICATIONS

OXYGEN SENSOR (O2S)

Note. Malfunctioning O2S may set Code 13, 44 or 45. For additional testing, see TESTS W/CODES - 3.2L article.

1. Start engine, and warm it to operating temperature. Ensure vehicle is operating in closed loop. Unplug oxygen sensor connector at sensor. Using Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, connect DVOM (on voltmeter scale) between ground and oxygen sensor connector (sensor side).
2. Place a short jumper wire in sensor lead (computer side). While holding jumper wire in one hand, alternately touch negative battery terminal and then positive battery terminal with other hand. DO NOT touch sensor lead directly to battery.
3. Monitor DVOM reading. When negative battery terminal is touched, oxygen sensor output voltage should increase (up to one volt). When positive battery terminal is touched, oxygen sensor output voltage should drop (as low as .1 volt). If oxygen sensor does not respond as indicated, replace sensor. To test oxygen sensor heater, go to «CHART C-1F»(ref-15977-S23121206212000122900000) under DIAGNOSTIC CHARTS. For park/neutral switch testing procedure, proceed to appropriate «CHART C-1A»(ref-15977-S15803784852000122900000) under DIAGNOSTIC CHARTS. Relay is mounted on left side of auto transmission. S witch is also called automatic transmission mode switch.

POWER STEERING PRESSURE SWITCH

Power steering pressure switch is located in power steering pump housing. To test power steering pressure switch, proceed to appropriate CHART C-1E under DIAGNOSTIC CHARTS. Replace switch if defective.

THROTTLE POSITION (TP) SENSOR

Note. Malfunctioning TP sensor may also set Code 21A or 21B. For additional testing, see TESTS W/CODES - 3.2L article.

1. Unplug TP sensor harness at sensor. Connect ohmmeter between Blue/Orange and Blue/Red wire terminals of sensor.
2. Resistance reading should vary smoothly as throttle is moved from idle to wide open throttle. Resistance reading should not drop or climb suddenly as continuity is checked. Replace sensor if defective.
3. To check sensor operating voltage, connect TP sensor harness. Sensor operating voltage may be monitored at ECM with ignition on. Note ECM location. See «ECM LOCATION»(ref-15977-S19028442802000122900000) . ECM LOCATION Model Location Passport Behind Left Kick Panel
4. Turn ignition on. DO NOT start engine. Using digital voltmeter, backprobe ECM connector terminals to check if 5-volt TP sensor reference signal exists. Reference signal should exist at ECM terminal A1 (Blue/Orange wire).
5. If 5-volt reference signal is not present, check for short to ground in 5-volt reference line from ECM to TP sensor. If no short is present, ECM is defective.
6. If 5-volt reference signal is present, test TP sensor input signal at appropriate ECM terminal. Connect negative voltmeter probe to ground. Backprobe ECM terminal with positive voltmeter probe at ECM terminal D6 (Blue/Red wire).
7. With engine running, voltage should be about .5 volt at idle and increase to about 5 volts at wide open throttle. If voltage reading is incorrect, check wiring to TP sensor. If wiring is okay, replace TP sensor.

TRANSMISSION TEMPERATURE SENSOR

Disconnect transmission temperature sensor. Measure resistance across terminals of sensor connector. Replace sensor if resistance is not within specification. See TRANSMISSION TEMPERATURE SENSOR RESISTANCE .

TRANSMISSION TEMPERATURE SENSOR RESISTANCE

VEHICLE SPEED SENSOR (VSS)

Note. Malfunctioning vehicle speed sensor may set Code 24 or 63. For additional testing, see TESTS W/CODES - 3.2L article.

Scheme 119

Scheme 120

1. Vehicles have one VSS located in vehicle speedometer and one mounted on left rear of transmission. Transmission mounted VSS sends signal to speedometer VSS, which controls needle movement and sends signal to ECM and cruise control.
2. For testing speedometer VSS, remove speedometer from meter assembly. Using DVOM, measure resistance value between terminals 4P and GND. (Scheme 119) Resistance should be 13,500-16,000 ohms. If resistance is not as specified, replace speedometer assembly.
3. For testing transmission mounted VSS, remove VSS from transmission by rotating sensor body. Connect jumper wire between VSS connector terminal No. 1 and positive battery terminal. (Scheme 119) WARNING: DO NOT connect battery voltage to VSS connector terminal No. 3; VSS damage will result.
4. Connect jumper wire between VSS connector terminal No. 2 and negative battery terminal. Connect 1.3k-5k ohm resistor (1/4 watt or more) between VSS connector terminals No. 1 and 3.
5. Using a DVOM, measure voltage across resistor while rotating sensor shaft slowly. With one rotation of sensor shaft, voltage should fluctuate 4 times. Ensure voltage fluctuates between 10-14 volts and 2 volts or less. If sensor voltage is outside specification, replace VSS.

Electronic Spark Control Module

See TIMING CONTROL SYSTEMS under IGNITION SYSTEM.

IAC Motor

This component is called Idle Air Control (IAC) valve. See IDLE CONTROL SYSTEM .

A/C Compressor Relay

See A/C CLUTCH CONTROL under MISCELLANEOUS CONTROLS.

Scheme 121

ECM Main Relay

1. Remove relay from connector. Test for continuity between terminals No. 3 and 5. (Scheme 121) Continuity should exist. Test for continuity between terminals No. 1 and 5. Continuity should not exist.
2. Apply battery voltage between terminals No. 2 and 4. Test for continuity between terminals No. 3 and 5. Continuity should not exist. Test for continuity between terminals No. 1 and 5. Continuity should exist. Replace relay if defective.

Air Regulator Solenoid

See IDLE CONTROL SYSTEM .

Scheme 122

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING - 3.2L article.

Pressure Regulator

1. Install fuel pressure gauge on fuel rail. Use care when installing fuel pressure gauge, as fuel lines are under pressure. Disconnect vacuum hose at pressure regulator.
2. Start engine and note fuel pressure. Ensure vacuum supply exists at vacuum line. Reconnect vacuum hose. Fuel pressure should decrease slightly. Replace regulator if pressure does not change.

Note. Malfunctioning pressure regulator VSV may set Code 25 or 53. For additional testing, see TESTS W/CODES - 3.2L article.

Pressure Regulator Vacuum Switching Valve (VSV)

1. Pressure regulator VSV and canister purge VSV share a 4-pin electrical connector and are mounted side by side. Ensure VSV hoses are connected to pressure regulator.
2. Disconnect electrical connector. Connector contains Black/White and Light Green/Yellow wires. Wires for pressure regulator VSV are Blue and Black.
3. Using ohmmeter, check resistance between Blue and Black wire terminals of VSV. Replace VSV if resistance is not about 35 ohms. Reconnect connector.
4. To check VSV operation with engine off, disconnect electrical connector. Apply battery voltage to Blue wire, and connect ground wire to Black wire. Replace VSV if operation of vacuum ports does not change. WARNING: Use care when installing fuel pressure gauge, as fuel lines are under pressure.
5. To check VSV operation with engine running, install fuel pressure gauge on fuel rail. Start engine and note fuel pressure. Fuel pressure should be about 35 psi (2.5 kg/cm 2 ). Disconnect electrical connector from VSV.
6. Apply battery voltage to Blue wire, and connect ground wire to Black wire of VSV. Fuel pressure should be about 42 psi (2.9 kg/cm 2 ). Replace VSV if pressure does not increase.

Scheme 123

1. Fuel pump relay is located under hood on right inner fenderwell inside relay box. Remove relay from connector. Test for continuity between terminals No. 1 and 3. (Scheme 123) Continuity should not be present. Test for continuity between terminals No. 1 and 2. Continuity should be present.
2. Apply battery voltage between terminals No. 4 and 5. Continuity should exist between terminals No. 1 and 3. Continuity should not exist between terminals No. 1 and 2. Replace relay if defective.

FUEL CONTROL

Note. Throttle valve switch and throttle position sensor are mounted on throttle body throttle shaft. M/T models use throttle valve switch. A/T models use throttle position sensor and throttle valve switch.

Fuel Injectors

1. Unplug fuel injector harness at injector. Using ohmmeter, measure resistance across terminals. Replace fuel injectors if resistance is not within specification. See «FUEL INJECTOR RESISTANCE SPECIFICATIONS»(ref-15977-S17184717602000122900000) .
2. With engine running, check fuel injector operating noise. Normal operation of injectors is indicated if a regular click is heard, which varies with engine speed. If click is not heard, replace injector.

FUEL INJECTOR RESISTANCE SPECIFICATIONS

Note. FUEL INJECTOR BALANCE TEST is also known as CHART C-2A.

See A/C CLUTCH CONTROL under MISCELLANEOUS CONTROLS.

IDLE AIR CONTROL VALVE

1. If Idle Air Control (IAC) valve is operating improperly, remove IAC valve from throttle body. Inspect IAC valve and throttle body bore for binding and clogged passages. Repair as necessary. If binding or clogged passages are not present, proceed to next step.
2. Disconnect electrical connector from IAC valve. Using ohmmeter, check resistance across terminals No. 1 and 2 and across terminals No. 3 and 4. (Scheme 133) Replace valve if resistance is not 40-80 ohms.
3. Using ohmmeter, check continuity across terminals No. 1 and 4 and across terminals No. 2 and 3. Replace IAC valve if continuity exists. If IAC valve tests okay, check for faulty connections at IAC valve and ECM. If connections are okay, check input devices used by ECM to control IAC valve operation. (Scheme 133)

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING - 3.2L article.

TIMING CONTROL SYSTEMS

Note. If problem develops with ESC, ECM will set Code 43. For additional testing, see TESTS W/CODES - 3.2L article.

EGR Transducer

1. Remove vacuum hoses from EGR transducer. Place finger over port "P" (VSV), and blow into port "Q" (EGRV). Air should pass through filter of EGR transducer.
2. Place finger over port "P" (VSV), and blow into port "R" (tube "S"). Air should pass through EGR transducer, but be restricted. Replace EGR transducer if defective.

EGR Vacuum Switching Valve

1. Disconnect vacuum hoses from VSV, located behind distributor. With ignition off, disconnect electrical connector from VSV. Using ohmmeter, check resistance between VSV terminals. Replace VSV if resistance is not 33-39 ohms. If resistance is okay, blow air into port "A" (to backpressure transducer). Air should pass through air filter and not through port "B" (to ported vacuum). Replace assembly if air passes through port "B".
2. Install electrical connector on VSV. Turn ignition on. Install jumper wire between terminals No. 1 and 3 of Diagnostic Link Connector (DLC). (Scheme 124) DLC is located under left side of dash.
3. Blow air into port "A". Air should pass from port "B". If air does not pass from port, check wiring between ECM and VSV. If wiring is okay, replace VSV.

EGR Valve

Using a vacuum pump, apply vacuum to EGR valve diaphragm. EGR valve diaphragm should hold vacuum. Ensure vacuum does not leak down and EGR valve diaphragm moves to a fully open position. Inspect EGR valve diaphragm for cracking. Check valve and seat for deformation and carbon deposits. Replace EGR valve if defective.

Scheme 124

PCV Valve

1. With engine running, remove PCV valve from rocker cover. Place thumb over end of valve to check for vacuum. If vacuum is present, go to step 3).
2. If no vacuum is present, remove PCV valve. If vacuum is present when valve is removed or engine dies, replace valve. If engine RPM changes little or does not change after removing valve from hose, replace vacuum hose between throttle body or intake manifold and PCV valve.
3. Turn ignition off. Remove PCV valve. Blow air into PCV valve from cylinder head side of valve. Ensure air flows through valve easily. DO NOT suck air through valve.
4. Blow air into intake manifold side of PCV valve. Ensure air does not flow through other side of valve. If valve does not function as indicated or valve does not rattle when shaken, replace PCV valve.

MISCELLANEOUS CONTROLS

Note. Although some controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

A/C CLUTCH CONTROL

For diagnosis of A/C clutch control, see CHART C-10 under DIAGNOSTIC CHARTS, A/C CLUTCH CONTROL DIAGNOSIS.

CHART C-1A - PARK/NEUTRAL SWITCH

Note. Test numbers refer to numbers on diagnostic chart.

Scheme 125

Scheme 126

1. This step checks for closed switch to ground in Park position and open switch in Drive ranges. ECM supplies voltage to Pink/Blue wire and senses closed switch when voltage drops to less than one volt. ECM uses this input to control idle speed, EGR operation and vehicle speed sensor diagnostics.
2. For access to diode wiring, remove lower cover of underhood fuse/relay box. (Scheme 125): Chart C-1A - Schematic Park/Neutral Switch (Scheme 126): Chart C-1A - Diagnostic Flowchart Park/Neutral Switch

CHART C-1D - MAP SENSOR OUTPUT

Note. Test numbers refer to numbers on diagnostic chart.

Scheme 127

Scheme 128

1. This step checks MAP sensor output voltage to ECM. Without engine running, this voltage represents a barometric reading to ECM.
2. Applying a vacuum reading of 10 in. Hg to MAP sensor should cause voltage to be 1.2-2.3 volts less than voltage in step 1). When applying vacuum to sensor, change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
3. This step checks vacuum hoses to sensor for leaks and restrictions. Ensure no other vacuum devices are connected to MAP sensor hose. (Scheme 127): Chart C-1D - Schematic MAP Sensor Output (Scheme 128): Chart C-1D - Flowchart MAP Sensor Output

CHART C-1E - POWER STEERING PRESSURE SWITCH

Power Steering Pressure Switch (PSPS) is normally open and circuit No. 901 (Green/Yellow wire) is about battery voltage. When power steering pump pressure increases, PSPS closes, causing voltage on circuit No. 901 (Green/Yellow wire) to fall to less than one volt.

ECM monitors voltage and increases idle speed when voltage decreases. If PSPS fails to close or open exists in circuit No. 901 (Green/Yellow wire), engine may stall when power steering pump pressure is high. If PSPS fails to open or short to ground exists in circuit No. 901 (Green/Yellow wire), idle speed may be affected and A/C relay will be de-energized.

Note. Test numbers refer to numbers on diagnostic chart.

Scheme 129

Scheme 130

1. Check scan tester instructions on how switch state will be displayed.
2. This step checks for a short to ground in circuit No. 901 (Green/Yellow wire).
3. This step simulates a closed switch. (Scheme 129): Chart C-1E Schematic Power Steering Pressure Switch (Scheme 130): Chart C-1E Diagnostic Flow Chart Power Steering Pressure Switch

CHART C-1F - OXYGEN SENSOR HEATER CHECK

Generator charging circuit supplies battery voltage to heater part of oxygen sensor. Heater warms oxygen sensor to allow a varying voltage to be produced by oxygen sensor.

Note. Test numbers refer to numbers on diagnostic chart.

Scheme 131

Scheme 132

1. This step will verify battery voltage is present for heater. Wire identified as Blue, HO2S signal circuit, could be Light Blue or Red/Blue.
2. This step checks ground circuit to heater.
3. This step checks heater element resistance. (Scheme 131): Chart C-1F Schematic Oxygen Sensor Heater Check (Scheme 132): Chart C-1F Diagnostic Flowchart Oxygen Sensor Heater Check

CHART C-2C - IDLE AIR CONTROL VALVE

Note. Test numbers refer to numbers on diagnostic chart. Typical wiring diagram shown. Wire color identification, see WIRING DIAGRAMS section at the end of this article. For testing purposes, IAC connector terminals correspond as follows: "A" is No. 1, "B" is No. 2, "C" is No. 3, and "D" is No. 4.

Scheme 133

Scheme 134

1. IAC tester is used to extend and retract IAC valve. Valve movement is verified by engine speed change. If engine speed does not change, valve can be retested when removed from throttle body.
2. This step checks quality of IAC movement in step 1). Engine speed should change smoothly with each flash of tester light in both extend and retract positions at 700-1500 RPM. If IAC valve is retracted beyond control range (1500 RPM), it may take many flashes in extend position before engine speed will begin to drop. Fully extending IAC valve may stall engine. This is normal condition.
3. Steps 1) and 2) verify proper IAC valve operation. This step checks IAC circuits. Each lamp on node light should flash Red and Green while IAC valve is cycled. While sequence of color is not important, check circuits for faults if either light is off or does not flash. Begin with poor terminal connections. (Scheme 133): Chart C-2C Schematic Idle Air Control Valve (Scheme 134): Chart C-2C Diagnostic Flowchart Idle Air Control Valve

CHART C-7A - EGR SYSTEM

ECM operates a Vacuum Switching Valve (VSV) to control vacuum to EGR valve. This solenoid is normally closed. ECM provides a ground to solenoid and VSV opens, allowing vacuum to EGR valve.

Engine control system operates within 2 block learn cells, a closed throttle cell and an open throttle cell. Open throttle cell is affected by EGR operation. When EGR system is operating correctly, block learn in both cells should be approximately the same. If EGR system is inoperative, block learn value at open throttle would increase, but block learn value at closed throttle would not change. This change or difference in block learn values is used to monitor EGR operation.

Scheme 135

Scheme 136