Mazda MX-5 1990 Workshop Manual page 276

F
CONTROL SYSTEM
Terminal Connection to
Abnormal voltage
Possible cause
1P
PIS pressure switch Always approx. OV
• PIS pressure switch malfunction
(Refer to page F- 140)
• Short circuit in wiring from ECU terminal 1 P to PIS
pressure switch
• ECl) malfunction
Always approx. 12V
• PIS pressure switch malfunction
(Refer to page F-140)
• Open circuit in wiring from ECU terminal 1 P to PIS
pressure switch
• Open circuit in wiring from PIS pressure switch to
ground
10 A/C switch Always approx. OV
• A/C switch malfunction (Refer to page U-25)
(with blower switch ON)
• Short circuit in wiring from ECU terminal 1
Q
to
A/C
switch
• Poor connection at ECU connector
• ECU malfunction
Always approx. 12V • A/C switch malfunction (Refer to page U-25)
(with blower switch ON)
• Open circuit in wiring from ECU terminal 1
Q
to A/C
(Blower fan OK)
switch
• Open circuit in wiring from AIC switch to blower con-
trol switch
1R
Fan switch Always approx. OV
• Open or short circuit in wiring from electric cooling
(Cooling fan OK) fan relay to ECU terminal 1 R
• ECU malfunction
1S
Blower control switch Always approx. OV • Short circuit in wiring from blower control switch to
(Blower fan OK) ECU terminal 1 S
• Poor connection at ECU connector
• ECU malfunction
Always approx. 12V
• Open circuit in wiring from blower control switch to
(Blower fan OK) ECU terminal 1 S
1U Headlight switch Always approx. OV
• Open or short circuit in wiring from headlight relay to
(Headlights OK) ECU terminal 1 U
1V
Neutral switch Always approx. OV
• Neutral switcn malfunction (Refer to page F-140)
Clutch switch
• Clutch switch malfunction (Refer to page F-139)
• Short circuit in wiring from ECU terminal 1 V to neu-
tral or clutch switch
• Poor connection at ECU connector
• ECU malfunction
• Open circuit in wiring from ECU terminal 1 V to neu-
tral and clutch switches
2A Ground More than OV • Poor contact at ground terminal
28 • Open circuit in wiring from ECU to ground
2C
20
2E Crank angle sensor Always approx. OV or
• Refer to Code No.02 troubleshooting
(Ne-signal)
approx.5V (Refer to page F-82)
2G Crank angle sensor
Always approx. OV or
• Refer to Code No.03 troubleshooting
(G-signal)
approx. 5V (Refer to page F-82)
2H Ground (California) Approx. 5V
• Open circuit in wiring from ECU terminal 2H to
ground
--
Approx. OV
• Short circuit in wiring from ECU terminal 2H to
(Federal and Canada)
ground
- -
21 Igniter Always Approx. OV
• Refer to Code No.01 troubleshooting
(Refer to page F-81)
2J Ground
Approx. 5V • Open circuit in wiring from ECU terminal 2J to
ground
F-132