Diagnosis & Repair Procedure

If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK under SYSTEM TESTS.
If DTC P1450 or P1451 is set along with P0106, perform appropriate test. See DTC P1450 OR DTC P1451 . If DTC P1450 or P1451 is not set, go to next step.
Turn ignition on. Using scan tool, observe MAP sensor parameter. Ensure MAP sensor value on scan tool indicates barometric pressure of about 100 kPa. Start engine and allow it to reach normal operating temperature. Ensure A/C is off. Momentarily increase engine speed to more than 3000 RPM, and return to idle. Record MAP sensor value. MAP sensor value should change by more than 33 kPa from key on engine off value of about 100 kPa. If MAP sensor value does not change as specified, check for poor connections or loose wires. Also check for restriction in MAP vacuum line caused by frozen MAP sensor filter. If no problem was found, go to next step. If MAP sensor value changes as specified, problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

Disconnect MAP sensor vacuum hose from intake manifold. Connect hand-held vacuum pump and gauge to vacuum hose. Using scan tool observe MAP sensor parameter while applied specified vacuum to MAP sensor. See MAP SENSOR OUTPUT SIGNAL table. If MAP sensor voltage is as specified, go to next step. If MAP sensor voltage is not as specified, replace MAP sensor. After repair, repeat DTC CONFIRMATION TEST .

MAP SENSOR OUTPUT SIGNAL ⁽¹⁾

Vacuum Applied In. Hg (kPa)

Scan Tool Display (kPa)

Zero

100

8 (27)

19.8 (67)

⁽¹⁾	With scan tool installed, ignition on, and specified vacuum applied to MAP sensor.

Check for intake system leaks and poor engine compression. Engine compression should be a minimum of 156 psi (11 kg/cm² ) at 250 RPM with a maximum variation of 14 psi. If no problems are found, substitute a known good ECM, and repeat DTC CONFIRMATION TEST .