Hey all,

I have a check engine light and got my codes. These are the stored codes:

09 - Water thermosensor
12 - Throttle sensor (full range)
13 - Pressure sensor (intake manifold pressure)
18 - Throttle sensor (narrow range)

I want to be sure I understand what I'm doing.

From my understanding, for the water thermosensor its either bad wiring or replace the sensor.

For the throttle sensor, I need to check the wiring and possibly adjust the screw?

For the pressure sensor, its either bad wiring or replace the sensor?


Thank you

 

The water thermosensor reads 2 to 3 volts w/key to on at the ECU's Green/White wire w/the engine cold. Voltage drops to close to .5 volts w/the engine completely warmed. If the reading is 5 volts then the wiring in the sensor plug is bad (perhaps one of the two wires in the plug is pulled back in the plug and the wire is not contacting the terminal at the sensor.

Your TPS should read 1 volt on the Green/Red wire (narrow range) w/key to on and the engine completely warmed and it should read 4.5 volts at wide open throttle (TPS plunger fully extended). Your TPS might be shot but the connector where the TPS plugs into the emission harness might be iffy.

The pressure sensor has 3 wires. One is ground. A second wire measures 5 volts w/key to on. The last wire is the output wire and w/key to on it should read at least a few volts or so. The exact number can be found in the online FSM.

 

Thank you! I will take a look at it this weekend. Luckily I have a paper copy of both the FSM and Haynes Manual so that should hopefully make things a bit easier.

 

I try not to take codes to literal . By all means check what the ecu is throwing out, but I like to always test the entire circuit related to code. I spend most of my time chasing wiring issues from po.