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OK, that may well be your problem. Hope you haven't driven it many miles with the T-stat upside down. Now you will be able to purge trapped air in the engine block.
I have driven many miles and thermostat was upside down for almost 1 month
Hope it won't cause any problems
You should be OK. The Jiggle valve serves two important functions:
1. It allows air pocket to pass during the initial filling/purging of the cooling system.
2. The small amount of flow through the jiggle valve allows your thermostat to sense the actual coolant temperature (as opposed to sensing the temperature of a pocket of dead-headed and stagnated coolant).
By installing the thermostat upside down, your thermostat is still opening at the correct coolant temperature.
The engine light pop up again after driving about 20 miles with both codes
P0171 ( system too lean bank 1 )
P0125 ( Insufficient Coolant Temperature For Closed Loop Fuel Control )
OK, I have a strong suspicion that the P0125 is causing the P0171.
Let's troubleshoot P0125... There are 3 likely causes:
1) Least likely - The coolant where the sensor is measuring does not get hot enough - Question: what does your temperature gauge show? Does your A/C blow hot air when you set it to MAX HEAT? Do your radiator fans come on with the car sitting idle (after driving for a few minutes)?
2) The temperature sensor is defective. Test: At 100 degC, you should measure around 100-ohm resistant across the terminals. At 25 degC, it should be 1,000-ohm.
3) Most likely - The wires or connector is defective.
It's time to connect the Techstream and get some coolant temperature readings. Note temperature changes after 2 minutes, 5 minutes, and 20 minutes. The ECM looks for these changes (namely, lack of change) to set P0125 DTC.
OK, I have a strong suspicion that the P0125 is causing the P0171.
Let's troubleshoot P0125... There are 3 likely causes:
1) Least likely - The coolant where the sensor is measuring does not get hot enough - Question: what does your temperature gauge show? Does your A/C blow hot air when you set it to MAX HEAT? Do your radiator fans come on with the car sitting idle (after driving for a few minutes)?
2) The temperature sensor is defective. Test: At 100 degC, you should measure around 100-ohm resistant across the terminals. At 25 degC, it should be 1,000-ohm.
3) Most likely - The wires or connector is defective.
It's time to connect the Techstream and get some coolant temperature readings. Note temperature changes after 2 minutes, 5 minutes, and 20 minutes. The ECM looks for these changes (namely, lack of change) to set P0125 DTC.
Temperature gauge reaches half in all conditions.
A/C is not blowing hot air when it's set to MAX HEAT.
I cheked radiator fans and they turn on after driving for few minutes.
The temperature sensor is OEM as I bought from dealer.
I didn't understand the test? Can you please explain more how to do this test?
I checked wire and connector and both are ok
The temperature readings after connecting Techstream are following :
Temperature after 2 minutes : 118 F
Temperature after 5 minutes : 169 F
Temperature after 20 minutes : 197 F
P0125 is set if the following conditions are not met:
1) Engine temperature increases by 15 DegF after 2 minutes,
2) Engine temperature increases by 15-35 DegF after 5 minutes,
3) Engine temperature increases by more than 35 DegF after 20 minutes.
From your description, your temperature sensor is working properly and your engine is warming up normally. I'm not sure why P0125 is set.
You mentioned that A/C is not blowing hot air when it's set to MAX HEAT. This indicates that you may have trapped air in the cooling system or possibly some blockage. However, this should not cause P0125 because your temperature sensor is reporting temperature changes to the ECM.
I'm attaching the factory troubleshooting steps for P0125 and P0171 for your review.
I know the LS430 has multiple coolant temperature sensors and I'm not an expert on Techstream, so to make sure that the temperature readings you saw on Techstream are from the same temperature sensor for P0125, try unplugging the sensor to see if the reading on Techstream drops out. If it does, then you're on the right temperature sensor and we'll have to look elsewhere for the cause of P0125. I'm still a bit hung up on the fact that hot coolant does not reach your heater coil to provide hot air on MAX HEAT (i.e. trapped air in the coolant system).
By the way, what is the temperature reading when you first started up the car?
You may still have air trapped in the system. With the engine at full operating temp, and the temperature setting on high / max heat in the cabin, can you jack up the front of the vehicle (or drive up ramps) to tilt the engine and coolant pipes helping to burp the system of possible trapped air?
Also, is your radiator cap defective? If it isn't properly opening and closing at the proper heat and pressure, it won't take coolant from the overflow reservoir as it is designed to do.
So you were looking at the correct temperature sensor reporting that your engine is warming up normally and sufficiently. I don't understand why P0125 is set. I'll read the troubleshooting steps on Post #22 again to see if I missed anything.
Just curious... Did you erase the DTC using just the OBDII, or did you disconnect the negative battery cable to hard-reset the ECM? The ECM "learn" to optimize engine performance, and can go out-of-wack sometimes. In which case, a hard-reset will give the ECM a fresh start. Another long shot!
I erased the DTCs using OBDII.
I'm afraid to disconnect the negative battery terminal because once appeared check engine and to erase that I pulled negative terminal and I ended up with a blank multi-information display and I had to replace the entire instrument cluster!
12-31-16, 11:15 AM
