Yay, more codes

[JMan689]

Once again my 94 decided to throw some codes at me when i started it this morning.

Ran both tests and got the following codes
Engine on: 116, 538, 536
Engine off: 214, 543, 556

Alright i already looked them up so i know what they are for.
- 116 - Engine Coolant (ECT) sensor out of range - ECT
Guessing this might mean i'm low on coolant?
- 536 - Brake On/Off Circuit Failure/Not Actuated During KOER
C/R
Since when i have to brake hard my parking brake light comes on someone said i might be low on fluid, could this trigger a code?
-538 - Insufficient RPM Change During KOER Dynamic Response Test
R
Ok this one just confuses me, i've never had a problem with the RPMs on the truck.
-214 - Error in Cylinder ID (CID) circuit or signal - Ignition Systems
I already pulled this one and when i had it in the shop to get a new shock mount installed i had them run the engine codes, they said they never found a problem it was just continuos memory codes. Should i take it back to the shop? clear the codes?
-543 - Fuel pump monitor circuit shows no power - Power / Fuel Pump Circuits
-556 - Fuel pump relay primary circuit fault - Power / Fuel Pump Circuits
Ok please correct me if i'm wrong, but if the fuel pump relay failed the pump would get no power and the truck wouldn't start. The relay caused past problems and it was replaced and i replaced the fuel pump, maybe 2-3 months ago.

Help as always is appreciated.

 

[MrShorty]

KOER 116 is indeed an ECT code. Usually caused by not having the engine fully warmed up when the test is run. Are you certain the engine was fully warmed up? This could also be caused by a faulty ECT or a stuck open thermostat or incorrect coolant level or anything that would interfere with the engine getting a correct reading from the ECT.

KOER 538 and 536 are almost always operator error codes. Review your instructions (and the stickies at the top of this forum). Then repeat the KOER test pressing the brake at the appropriate time and goosing the throttle at the cue from the PCM.

CM 214 indicates that at some point in the past, the computer lost the CID signal, which, on your '94, is generated by the CMP sensor. If there aren't other symptoms, the first thing to do would be to clear CM (review instructions), test drive, and see if the CM 214 comes back. If it does come back, then you should probably review the CId circuit and see if you can find a problem. If it doesn't come back, then the fault is either and old fault or it is intermittent.

Were the 543 and 556 KOEO (before separator pulse) or CM (after separator pulse) codes? For the longest time, I would occasionally get a CM 543 from my '92. I cleared it from CM and it didn't come back immediately. Then one day it wouldn't start immediately. Then it happened again. Eventually I was able to locate a bad connection in the fuel pump circuit between the fuse and the relay. In any case, the exact diagnostic procedure will depend on whether it is CM or KOEO.

 

[BrooklynBay]

This is one of the links in # 25 in my list of useful threads: