Code 25: Barometric Pressure Sensor

NOTE: Barometric (BARO) pressure sensor is built into airflow sensor. For code 25 test purposes, the airflow sensor will be referred to as the BARO pressure sensor. For component terminal identification, see AIRFLOW SENSOR under TERMINAL IDENTIFICATION in this article. For wiring diagrams, see WIRING DIAGRAMS .

Manufacturer does not provide component testing procedure without scan tool. Turn ignition switch to ON position. Using scan tool, read sensor pressure. See BARO PRESSURE SENSOR SPECIFICATIONS table. If pressure is not as specified, replace BARO pressure sensor. If pressure is as specified, go to next step.

BARO PRESSURE SENSOR SPECIFICATIONS

Altitude: Ft. (M)	Pressure: In. Hg
0 (0)	29.92
1969 (600)	27.95
3937 (1200)	25.98
5906 (1800)	24.02

Disconnect BARO pressure sensor connector. Using DVOM, check for continuity between chassis ground and specified BARO pressure sensor connector terminal. See BARO PRESSURE SENSOR GROUND CIRCUIT IDENTIFICATION table. If continuity does not exist, repair wiring harness as necessary. If continuity exists, go to next step.

BARO PRESSURE SENSOR GROUND CIRCUIT IDENTIFICATION

Application	Terminal No.
All Models	5

With BARO pressure sensor disconnected, disconnect PCM connector. Check for continuity between specified PCM connector terminal and BARO pressure sensor connector terminal. See BARO PRESSURE SENSOR TO PCM CIRCUIT IDENTIFICATION table. If continuity does not exist, repair wiring harness as necessary. If continuity exists, go to next step.

BARO PRESSURE SENSOR TO PCM CIRCUIT IDENTIFICATION

Application	BARO Terminal No.	PCM Terminal No.
All Models	2	65

With BARO pressure sensor connector and PCM connector disconnected, turn ignition switch to ON position. Check for voltage between chassis ground and BARO pressure sensor connector terminal No. 1. If voltage is not 4.8-5.2 volts, replace PCM. If voltage is as specified, condition required to set code is not present at this time. Test is complete. Intermittent problem may exist. See TESTS W/O CODES - 1.5L article.
With BARO pressure sensor connector disconnected, turn ignition switch to ON position. Check for voltage between chassis ground and BARO pressure sensor connector terminal No. 1. If voltage is not 4.8-5.2 volts, repair wiring harness as necessary. If voltage is as specified, go to next step.
With BARO pressure sensor connector and PCM connector disconnected, ground PCM connector terminal No. 16. Using DVOM, check for continuity between chassis ground and BARO pressure sensor connector terminal No. 1. If continuity does not exist, repair wiring harness as necessary. If continuity exists, condition required to set code is not present at this time. Test is complete. Intermittent problem may exist. See TESTS W/O CODES - 1.5L article.