1994 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE

Sensor Range Charts

Sensor operating range information can help determine if a sensor is out of calibration. An out-of-calibration sensor may not set a trouble code, but it may cause driveability problems.

NOTE: Unless stated otherwise in test procedure, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.
COOLANT TEMPERATURE SENSOR RESISTANCE (1)

Temperature - °F (°C) Ohms
68 (20) 2100-2900
122 (50) 680-1000
176 (80) 300-330
(1) Measure resistance across sensor terminals.
EGR TEMPERATURE SENSOR RESISTANCE (1)

Temperature - °F (°C) Ohms
212 (100) 76,770-93,830
(1) Heat sensor in water and measure resistance across sensor terminals.
FUEL TEMPERATURE SENSOR RESISTANCE (1)

Temperature - °F (°C) Ohms
68 (20) 2100-2900
122 (50) 680-1000
176 (80) 300-330
(1) Measure resistance between sensor terminals at pressure regulator.
HEATED OXYGEN SENSOR VOLTAGE (1)

Condition Volts
Lean 0-0.3
Rich 0.6-1.0
(1) Measure voltage between oxygen sensor terminal and ground, voltage should continuously change. Measure heater resistance between terminals "A" and "C" at sensor. Resistance should be 3-1000 ohms.
CLOSED THROTTLE POSITION SWITCH CONTINUITY (1)

Position Reading
Closed Throttle Continuity
Open Throttle No Continuity
(1) Check continuity between terminals No. 2 and 3 at sensor. See Fig 1 .
THROTTLE POSITION SENSOR RESISTANCE (1)

Position Ohms
Closed Throttle 700
Partially Open 700-5000
Wide Open Throttle 5000
(1) Measure resistance between terminals No. 4 and 5 at sensor. See Fig 1 .
MASS AIRFLOW SENSOR VOLTAGE (LOW RPM) (1)

Application Terminal No Volts
Q45 "1" 1.0-1.4
(1) Measure voltage between ground and indicated airflow meter terminal with engine idling at normal operating temperature.
MASS AIRFLOW SENSOR VOLTAGE (HIGH RPM) (1)

Application Terminal No Volts
Q45 "1" 1.4-1.9
(1) Measure voltage between ground and indicated airflow meter terminal with engine running at 2000 RPM at normal operating temperature.
Fig 1: Throttle Position Sensor/Closed Throttle Switch Terminal ID
G90A15222Courtesy of NISSAN MOTOR CO., U.S.A.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.