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What is your question?
I JUST BOUGHT A OLDS INTRIGUE 3.8L. IT HAD A BAD LOW COOLANT SENSOR WHICH I REPLACED. I ALSO REPLACED THE ENG .TEMP. SENDER , THERMOSTST & GASKET ,HOSES,& RADIATOR CAP. FLUSHED THE ENGINE &RADIATOR A REFILLED WITH FRESH DEXCOOL ANTIFREEZE, FOR THE WINTER. SHORTLY THEREAFTER WHILE DRIVING I NOTICED THE ENGINE WAS GETTING TOO WARM. I OPENED THE HOOD AND NOTICED THE COOLING FANS WERE NOT RUNNING. I HAD TO MAKE UP A JUMPER WIRE FROM THE BATTERY TO A FAN TO GET HOME.MY OBD SCANNER READS "P1651 CIRCUIT /OUTPUT DRIVER MODULE (QUAD DRIVER ) 'B' QUICKSET FAULT ( SATURN) 2. FAN 1 RELAY CONTROL CIRCUIT. IN THE LAST 2 WEEKS I HAVE CHECKED THE RELAYS FANS MOTORS ALL CONNECTORS AND WIRING WITH NO SUCESS .A CONTINUITY METER SHOWS THE DARK GREEN GRD.WIRE FROM RELAY #1 TO THE COMPUTER BLUE CONNECTOR PIN #5 AS PER WIRING DIAGRAM APPEARS TO BE GOOD. BUT FANS DO NOT WORK. IF I RUN A JUMPER FROM PIN #5 TO THE #1 RELAY WIRE , THE FANS WILL RUN CONSTANTLY. IS THE COMPUTER BAD? WHAT THE HECK IS GOING ON. WHAT AM I MISSING? GEORGE W.... (FORMER GM PROF. MECHANIC IN 70,S) 35
2 Replies
You have a control problem that is not turning on the coolant fan. You need a scanner that can read serial data to see at least two things. One engine temp and cooling fan on or off. the fan will engage at around 220 degrees plus or minus 5. The P1651 code is due to you bypassing the relay. I know this for a fact, because I have bypassed my cooling fan relay and got that code. It will not cause any damage to the PCM. You'll just have a check engine light. If you want to try something, to see if the computer has the ability to engage the fan. Take all jumper leads off. Plug everything back in where it is supposed to be. Now pay close attention to what I'm about to tell you. Unplug the engine coolant temp sensor. Take a small paper clip and jumper across the plug leads. With the key in the run position the computer has to command the fan to come on by providing a ground via the green wire at the relay to energize the fan. You say you have verified a complete circuit from the coolant sensor to the PCM. Then assuming relay is good you might have a possible bad PCM. The proper way is to scan it for serial data and command. You will not be able to do this with a generic OB2 code reader. I personally chose to bypass my coolant fan relay because of the extreme temperatures I see in Southwest Florida. If you do bypass the cooling fan relay it will not harm the PCM. I have done it for at 8 years with no other problems. All you have to do is cut the green wirw at the cooling fan relay and the wire on the connector side take to ground. Of course if you do bypass it you will have a check engine light on with a P1651 code. That is not to say that you won't have some other code set. If i recall you said you had an OBD2 code reader so you could scan it ever so often. If you have any mor questions contact me at jmgrhm30@gmail.com
you need a scanner to monitor the operation of the fans. the temp has to be 209 degrees to kick. do they work with the ac?? you need 150 lbs on the high side to kick them. check the plug on the coolant sensor. saturn has tons of issues with the 3rd wire corroding and causing the no fans operation. Roy be carefull with the other answer. in pa. we have the issue with the check engine light for emission. you also will not know when you have other issues. Roy
Roy is correct. I forgot I don't have to deal with emmissions testing. He's correct that a check engine light in Pa. will fail test. The coolant sensor on this vehicle is two wire not three.
the plug on the coolant sensor is good & no the fans don't work even with the ac on. the ac seems to be working fine. it just passed emission & inspection no problem. emissions were very low i was with the mechanic when he did the test . he said it was very good.
thank you for your reply i wil try what you suggest if i remember when i started with this after i had already replaced the low coolant sensor i was thinking maybe it could be defective i think i already tried putting a paper clip in the low coolant sensor plug & it still did nothing. i will have to try it again. if i do need to bypass the relay as you did what do i need to do? cut the green wire at the relay & ground the wire at the computer connector end is that right? george the scanner i have is craftsman model#87702 CAN OBD2 DIAGNOSTIC TOOL. I JUST GOT THIS RECENTLY BECAUSE OF THIS PROBLEM & SOLD MY BASIC GENERIC READER.I DON'T THINK THIS UNIT CAN READ SERIAL DATA...THE P1651 CODE COMES BACK AFTER BEING ERASED FROM MEMORY & JUMPER REMOVED. SO THE CODE IS NOT JUST COMING UP BECAUSE I JUMPED THE RELAY... THANKS.. /
Low coolant sensor has nothing to do with fan operation. the LOW COOLANT SENSOR is on the side of the radiator. When you find the ENGINE COOLANT TEMPERATURE sensor and jumper the two wire plug your fan should turn on. You really need a real scanner to properly fix this car.