Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Mazda B4000, 2003 Mazda B3000, and 2003 Mazda B2300. However, it is still accessible from the selected car via links, so may be relevant.

If QUICK TEST was not performed, go to QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If QUICK TEST was performed, go to next step.

Check MAP PID - Obtain local barometric pressure reading. Access MAP PID. If MAP PID is not available, disconnect PCM 104-pin harness connector. Connect breakout box to PCM harness connector and PCM. See Figure . With KOEO, measure voltage at breakout box terminal No. 63 (MAP circuit). If MAP PID is available, with KOEO compare PID voltage reading with MAP SENSOR VOLTAGE SPECIFICATIONS table. If PID voltage reading matches voltage in table, go to next step. If PID voltage reading does not match voltage in table, for DTC P0108, go to step 6 . For DTC P0107 and P0109, go to step 5 .

MAP SENSOR VOLTAGE SPECIFICATIONS

Barometric Pressure In. Hg (kPa)	Volts
3.0 (10.0)	0.5
6.8 (23.1)	1.0
10.7 (36.1)	1.5
18.5 (62.3)	2.5
20.4 (68.8)	2.6
22.3 (75.4)	3.0
26.2 (88.4)	3.5
27.2 (91.7)	3.6
28.1 (95.0)	3.75
29.1 (98.2)	3.8
30.1 (101.5)	4.0
31.1 (104.8)	4.12
32.0 (108)	4.25

Check MAP Transition With Vacuum - Remove MAP sensor from intake manifold. Ensure MAP sensor 4-pin harness connector is connected. Access MAP PID. If MAP PID is not available, measure at breakout box terminal No. 63 (MAP circuit). Slowly apply 18 in. Hg of vacuum to sensor and watch voltage for smooth transition down as vacuum is applied. If voltage reading decreases smoothly with vacuum application, go to next step. If voltage reading does not decrease smoothly with vacuum application, replace faulty MAP sensor. After repair, go to step 11 .
Check MAP Output With Vacuum - Subtract applied vacuum from local barometric pressure reading. See MAP SENSOR VOLTAGE SPECIFICATIONS table and compare with voltage specification in table. If voltage reading compares with value in MAP SENSOR VOLTAGE SPECIFICATIONS table, failure is intermittent. See INTERMITTENT testing under SYSTEM TESTS. If voltage reading does not compare with value in MAP SENSOR VOLTAGE SPECIFICATIONS table, replace faulty MAP sensor. After repair, go to step 11 .
Check VREF Voltage To MAP Sensor - Disconnect MAP sensor 4-pin harness connector. Measure voltage between VREF (Brown/White wire) and SIG RTN (Gray/Yellow wire) circuits at MAP sensor harness connector. See Fig 1 . If voltage reading is 4-6 volts, go to next step. If voltage reading is not 4-6 volts, go to VEHICLE REFERENCE VOLTAGE testing under SYSTEM TESTS.

Fig 1: Identifying MAP Sensor Circuits (2.3L)
Courtesy of MAZDA MOTORS CORP.
Check MAP Circuit For Short To Power - Measure voltage at MAP sensor harness connector between MAP circuit (Light Green/Black wire) and battery negative terminal. See Fig 1 . If voltage reading is more than 10.5 volts, a short to VPWR is indicated. Go to step 8 . If voltage reading is 10.5 volts or less, go to next step.
Check MAP Signal Circuit - Turn ignition off. Connect fused jumper wire between VREF circuit (Brown/White wire) and MAP circuit (Light Green/Black wire) at MAP sensor 4-pin harness connector. See Fig 1 . With KOEO, measure voltage at breakout box terminal No. 63 (MAP circuit) and terminal No. 90 (PWR GND circuit). If voltage reading is same as VREF voltage, replace faulty MAP sensor. After repair, go to step 11 . If voltage reading is not same as VREF voltage, go to step 10 .
Isolate MAP Circuit For Short To VPWR - Turn ignition off. Disconnect PCM 104-pin harness connector. Connect breakout box to PCM harness connector only. See Figure . With KOEO, measure voltage between breakout box terminal No. 63 (MAP circuit) and terminal No. 103 (PWR GND circuit). If voltage reading is more than 10.5 volts, repair short circuit between MAP and VPWR circuits. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to step 11 . If voltage reading is 10.5 volts or less, MAP is shorted to VPWR inside PCM. Replace faulty PCM. After repair, go to step 11 .
Check For Shorted MAP Circuit In Harness - Turn ignition off. Disconnect scan tool from DLC. Measure resistance between MAP circuit (Light Green/Black wire) and SIG RTN circuit (Gray/Red wire) at MAP sensor 4-pin harness connector. See Fig 1 . Record reading. Measure resistance between MAP circuit (Light Green/Black wire) and chassis ground. Record reading. If either resistance reading is more than 10,000 ohms, MAP circuit is shorted to SIG RTN or ground inside PCM. Replace faulty PCM. After repair, go to step 11 . If either resistance reading is 10,000 ohms or less, repair short circuit in harness. After repair, go to step 11 .
Check MAP & SIG RTN Circuits For Open - Turn ignition off. Disconnect PCM 104-pin harness connector. Connect breakout box to PCM harness connector only. See Figure . Check continuity of MAP circuit (Light Green/Black wire) between MAP harness connector and breakout box terminal No. 63. See Fig 1 . Check continuity of SIG RTN circuit (Gray/Red wire) between MAP harness connector and breakout box terminal No. 91. If continuity is present at either circuit, MAP or SIG RTN circuit is open inside PCM. Replace faulty PCM. After repair, go to next step. If continuity is not present at either circuit, repair open circuit in harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. After repair, go to next step.
Verify Trouble Shooting Of DTCs Completed - Make sure all electrical connectors are reconnected. Clear DTCs from PCM memory using scan tool. Perform QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If the same DTC is present, replace faulty PCM. Repeat QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are present, test is complete.