Engine Controls - Sensor Operating Range Charts: Introduction

1994 Mercury Capri XR2, AutomaticSECTION Introduction

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.
BAROMETRIC PRESSURE SENSOR OUTPUT VOLTAGE (1)

Vacuum - In. Hg. (2) Volts
0 3.84
5 3.36
10 2.66
15 1.93
20 1.26
25 0.58
(1) Measure voltage between breakout box test pins BP and SIGRTN.
(2) Voltage may differ by plus or minus 15 percent.
ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE (1)

Temperature - °F (°C) Ohms
-4 (-20) 14,600-17,800
68 (20) 2200-2700
176 (80) 290-350
(1) Measure resistance between breakout box test pins ECT and SIGRTN.
IGNITION DIAGNOSTIC MONITOR VOLTAGE (1)

RPM Volts
500 1.103
1000 1.257
1500 1.542
2000 1.768
2500 2.06
3000 2.15
3500 2.26
4000 2.50
4500 2.47
5000 2.40
(1) Measure voltage between breakout box test pins IDM and VPWR.
TP SENSOR OUTPUT VOLTAGE

Throttle Opening (1) Voltage
1/8 1.00
1/4 1.60
3/8 2.37
1/2 2.74
5/8 3.15
3/4 3.43
7/8 3.60
Full Open 4.02
(1) Voltage may differ by 15 percent.
VOLUME AIRFLOW METER VOLTAGE (1)

Door Opening (2) Volts
1/8 3.24
1/4 5.60
3/8 5.62
1/2 5.83
5/8 6.02
3/4 6.57
7/8 7.46
Fully Open 7.87
(1) Measure voltage between breakout box test pins VAF and SIGRTN.
(2) Voltage may differ by plus or minus 15 percent.
IAT SENSOR RESISTANCE (1)

Temperature °F (°C) (2) Ohms
-4 (-20) 10,000-20,000
32 (0) 4000-7000
68 (20) 2000-3000
104 (40) 900-1300
140 (60) 400-700
(1) Measure resistance between breakout box test pins IAT and SIGRTN.
(2) Resistance may differ by plus or minus 15 percent.
RENDER: 1.0x

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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.