Diagnostic Aids

NOTE: After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all electronic engine control systems are working properly and DTCs are no longer present.

Perform this test when directed by QUICK TEST. This test is only intended to diagnose the following components and circuits:

Manifold Absolute Pressure (MAP) sensor.
Wiring Harness Circuits (VREF, SIG RTN & MAP SIG), see Fig 1.
Powertrain Control Module (PCM).

Manifold Absolute Pressure (MAP) sensor functions are as follows:

Smoke Control

MAP signal is used to control smoke by limiting fuel quantity during acceleration until a specified boost pressure is obtained.

Dynamic Injection Timing

Optimizes injection timing for boost pressure measured.

Fault Detection & Management

A MAP signal that is detected by PCM to be out of range or at an incorrect value for specific conditions will cause PCM to ignore MAP signal and operate engine from an inferred boost pressure signal.

Fig 1: Identifying Manifold Absolute Pressure Sensor Circuits

Courtesy of FORD MOTOR CO.

MAP SENSOR SPECIFICATIONS

Psi (kPa)

⁽¹⁾ Volts

11.5 (80)

1.1

14.7 (101)

1.5

20 (138)

2.2

25 (172)

2.8

30 (206)

3.6

35 (242)

4.3

⁽¹⁾	A variation of plus or minus .3 volt is acceptable.