1995 Ford Bronco 5.0 and auto. Sometimes no start, somtimes runs rough and check engine light is on. Checked fuel pressure at rail. Normal. Brought an Actron computer error code decoder and here is what I got.

Key on engine off: 116636123565116636123565123123.

Key on engine on: 1235651235651111111

I then unhooked negative ground for 10 minutes to reset computer. I started the engine and the check engine light comes back in less than a minute. Turned off engine. Ran ran another Keyon Engine off. I got the following: 123565123565.

Do you thinks the problem is the TPS?

Any help appreciated. I've never ran codes before and don't know what I'm looking at.

 

Some one will come along thats better at this than me but i will take a shot.
code 123 throttle position sensor circut below max voltage
code 565 canister purge circut failed

 

First off ALWAYS disconnect positive to reset the computer. Leaving the positive connected with nowhere for voltage to go can be catastrophic if there is a dead short in the system somewhere. In leaving the negative connected, the capacitors and semiconductors can also discharge through the body/frame of the vehicle instead of continuing to retain voltage. This is one of the reasons for removing power to the computer as well.

So, you are dealing with Codes 12, 35, and 65 OR Codes 123 and 565. How does the reader break them down? By 1995 I would think that MOST ECM's are spitting out three-digit Codes but its hard to be certain with the way they are written here. In looking at the symptoms, either COULD be true.

Code 123 - can be verified by taking a voltage reading at the TPS connector with the TP sensor disconnected from the harness. The BROWN/WHITE wire should show approximately +5VDC with the key on. If not, you have a break in this wire between the TPS connector and the ECM (Pin 47).

If the first step yielded a correct voltage reading, the next step is to reconnect the TP sensor and take a voltage reading from the GREEN/WHITE wire with the key on and the throttle closed. This voltage reading should fall between +0.2 and +0.39 VDC. If it does NOT, replace the TP sensor.

If, for some reason, it is determined that you are actually getting TWO-digit Codes and not three-digit Codes, let us know because Codes 12, 35 and 65 are COMPLETELY different animals.

If the second step yielded an acceptable voltage reading, take the same voltage reading on the GREEN/WHITE wire AGAIN. However, this time check the reading with the throttle wide open. The voltage reading should not exceed +4.84 VDC. If it does NOT, replace the TP sensor.

Code 565 - is as straight forward as they come... Pat already said it. The circuit in question actually drives the purge solenoid on the canister. The connector is a two-wire at the solenoid that should have a GREY/YELLOW wire and a RED wire. Check the connection at the solenoid and make certain you have battery (+12 VDC approx.) between the RED wire and the frame (NEGATIVE) of the truck. The ECM controls when the purge solenoid actually gets NEGATIVE (via the GREY/YELLOW wire) to complete the circuit and thus purge the canister.

If, for some reason, it is determined that you are actually getting TWO-digit Codes instead of three-digit Codes, let us know right away because Codes 12, 35 and 65 are COMPLETELY different animals!