1991 Suzuki Samurai JSFACTORY OEM SERVICE PROCEDURE

Pressure Sensor

  1. Sensor is mounted to right center of firewall. To test pressure sensor on vehicle, turn ignition on. Connect voltmeter between ground and indicated ECM connector terminal (backprobe ECM terminal). See PRESSURE SENSOR OUTPUT VOLTAGE (ON-VEHICLE)  table.
  2. If voltage is not within specification, see Code 31 or 32 in TESTS W/CODES article in the ENGINE PERFORMANCE Section. To test pressure sensor off vehicle, see PRESSURE SENSOR OUTPUT VOLTAGE (OFF-VEHICLE)  table. If voltage is not within specification, replace pressure sensor.
PRESSURE SENSOR OUTPUT VOLTAGE (ON-VEHICLE)

Altitude (Feet) Vacuum (In. Hg) (1)(2) Output Voltage
0 30 3.6-4.4
1000 29 3.5-4.2
2000 28 3.4-4.1
3000 27 3.2-4.0
4000 26 3.1-3.8
5000 25 3.0-3.7
6000 24 2.9-3.6
7000 23 2.8-3.4
8000 22 2.7-3.3
9000 21 2.6-3.2
10,000 20 2.5-3.1
(1) Pressure sensor output voltage is tested at ECM connector. See ECM LOCATION table. Before testing pressure sensor output voltage, ensure ECM supply voltage is 4.75-5.52 volts at A23 Gray/Red wire terminals of ECM connector.
(2) Output voltage is checked at A22 Gray/Green wire terminals of ECM connector.
PRESSURE SENSOR OUTPUT VOLTAGE (OFF-VEHICLE)

Altitude (Feet) Vacuum (In. Hg) (1)(2) Output Voltage
0 30 3.4-3.8
1000 29 3.3-3.7
2000 28 3.1-3.6
3000 27 3.0-3.5
4000 26 2.9-3.3
5000 25 2.8-3.2
6000 24 2.7-3.1
7000 23 2.6-3.0
8000 22 2.5-2.9
9000 21 2.4-2.8
10,000 20 2.3-2.7
(1) Pressure sensor output voltage is tested with three 1.5-volt batteries connected in series. Positive lead is connected to Gray/Red wire terminal. Connect negative lead to Gray/Yellow wire terminal.
(2) Output voltage is checked at Gray/Green wire terminal of pressure sensor connector.
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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.