I need some help figuring out what these trouble codes mean, 24, 25 and 31

MMFID

MEMBER
1994 TOYOTA PICKUP
234,000 MILES

I did the trouble code with the check engine light and received codes 24, 25 and 31 and do not understand the meanings. Code 24 says "intake air temp signal fault. Code 25 says air/fuel ratio lean. And code 31 says Air flow meter circuit or vacuum sensor signal fault.I have checked all vacuum lines and all are good. I can't figure what I am to fix. My truck is at one point idle low and volts low, when the volts go up the idle goes up. Mpg's has dropped and it is all together running badly. The check engine was on once before with only code 25 showing, it did go off for about a month after changing the plugs. I had one bad burnt plug.

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Diagnostic Trouble Codes - 1994
Toyota

12

G, NE Signal Circuit No. 1.

13

G, NE Signal Circuit No. 2.

14

Ignition Signal.

16

ECT Control Signal.

21

Oxygen Sensor (OS) Signal.

22

Water Temperature Sensor (THW) Signal.

24

Intake Air Temperature Sensor (THA) Signal.

25

Air/Fuel ratio lean.

26

Air/Fuel ratio rich.

27

Sub-oxygen sensor signal.

31

Manifold Absolute Pressure Sensor Signal.

41

Throttle Position Sensor (TPS).

42

Vehicle Speed Sensor (VSS) Signal.

43

Starter Circuit Signal.

51

Switch Condition Signal.

52

Knock Control Signal.

71

EGR system malfunction.