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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Toyota
Satisfied Customers: 3458
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles
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Just failed a smog test with my 2007 Prius : Service fault

Customer Question

Hi there- just failed a smog test with my 2007 Prius
JA: Sometimes the difference between passing and failing a smog test can be just a few quick repairs. Luckily, the mechanic I'm going to connect you with will have just the information you need to get this fixed fast. How many miles are on the car?
Customer: Service fault codes P1116 and P1121
JA: Tell me a bit more about what's going on so he can help you best.
Customer: 157883 miles
JA: Are you hoping to fix this yourself?
Customer: no
JA: OK! The Toyota Mechanic will help you with the diagnostics so you are sure to get this fixed right. Is there anything else the Toyota Mechanic should be aware of about your Toyota?
Customer: nope
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Toyota Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Toyota
Expert:  Chad Farhat replied 1 year ago.

Hi my name is ***** ***** i will be assisting you

Expert:  Chad Farhat replied 1 year ago.

let me look up these codes and be right back with you

Customer: replied 1 year ago.
great thank you
Expert:  Chad Farhat replied 1 year ago.

The P1116 : 1- CHT sensor bad 2- or the coolant system is clogged need flushing , or radiator clogged

2007 Toyota Prius L4-1.5L (1NZ-FXE) Hybrid Save Article Select Print Option Complete Article Text Only Image(s) Only DTC P1116 Coolant Temperature Sensor Circuit Stack for Coolant Heat StorageDESCRIPTIONHINT: Although each DTC title says "Coolant Temperature Sensor", these DTCs are related to the coolant heat storage tank outlet temperature sensor.This system uses an electric pump to supply hot coolant stored in the coolant heat storage tank into the cylinder head of the engine, in order to optimize engine starting combustion and reduce the amount of unburned gas that is discharged while the engine is started. Before the engine starts, the ECM operates the electric water pump to direct the hot coolant in the heat storage tank into the engine, in order to heat the cylinder head (this process is called "preheat mode"). The duration of the operation of the electric water pump is variable, depending on the temperature of the cylinder head. During the normal operation of the engine, the water valve opens the passage between the cylinder head and the heater and closes the passage between the cylinder head and the tank. During preheat mode in which the cylinder head is heated, the water valve opens the passage between the tank and the cylinder head, in order to allow the coolant to flow from the tank to the cylinder head. At this time, in order to warm up the intake port quickly before the engine is started, the coolant flows in the reverse direction.The sensor for the system, which is provided at the tank outlet, is constructed similarly to the engine coolant temperature sensor and is connected to the ECM. The CHS tank outlet temperature sensor has a built in thermistor, whose resistance varies with the coolant temperature.MONITOR DESCRIPTIONThe coolant heat storage (CHS) tank outlet temperature sensor is used for monitoring coolant temperature in the vicinity of the outlet port of the heat storage tank of the CHS system. The resistance of the sensor increases when the CHS tank outlet temperature is low, and conversely, the resistance decreases when the temperature is high. The changes in resistance are reflected in the voltage that is output by the sensor. The ECM monitors the sensor voltage and uses this value to control CHS system properly.If the sensor output voltage deviates from the normal operating range, the ECM determines that the CHS tank outlet temperature sensor circuit has malfunctioned, and sets a DTC.Examples:
1. No changes occur in the CHS tank outlet temperature sensor signal (over 1 °C [1.8 °F]) after a predetermined length of time has elapsed from the start of the coolant recovering.
2. A significant difference (over 25 °C [45 °F]) exists between the engine coolant temperature signal and the CHS tank outlet temperature sensor signal after a predetermined length of time has elapsed from the start of the coolant recovering.INSPECTION PROCEDURECAUTION: Be careful when replacing any part in the system or changing the coolant because the coolant in the heat storage tank is hot even if the engine is cold.HINT:
- To check the coolant heat storage (CHS) system, the ECM may cause the water pump of the CHS system to operate 5 hours after the power switch has been turned OFF.
- Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.2007 Toyota Prius L4-1.5L (1NZ-FXE) Hybrid Save Article Select Print Option Complete Article Text Only Image(s) Only Zoom and Print Options T-SB-0231-12November 29, 2012MIL "ON" DTC P1121Service CategoryEngine/Hybrid SystemSectionCoolingMarketUSA
ApplicabilityIntroductionSome customers with 2004 - 2007 model year Prius vehicles may experience a MIL "ON" condition with Diagnostic Trouble Code (DTC) P1121, Coolant Flow Control Valve Position Sensor Stuck. Use the repair procedure below to address this condition.Production Change Information
This bulletin applies to vehicles produced BEFORE the Production Change Effective VINs shown.
Parts Information
Warranty Information
Required Tools & EquipmentRepair Procedure1. Check DTCs and confirm P1121 is present.
2. Remove the engine under cover LH.
3. Drain the engine coolant.Refer to the Technical Information System (TIS) applicable model and model year Repair Manual:^ 2004 / 2005 Prius:Engine/Hybrid System - Cooling - "Engine Coolant (1NZ-FXE): Replacement"^ 2006 / 2007 Prius:Engine/Hybrid System - Cooling - "1NZ-FXE Cooling: Coolant: On-vehicle Inspection"
4. Mark the upper coolant hose (hose to heater core). Take note of the original location of all coolant hoses.5. Remove the electrical connector on the coolant flow control valve.6. Remove all three coolant hoses on the coolant flow control valve.7. Remove the coolant flow control valve from the vehicle body.8. Install the replacement coolant flow control valve in reverse order of removal.9. Install the engine under cover LH.10. Refill engine coolant.Refer to TIS applicable model and model year Repair Manual:^ 2004 / 2005 Prius:Engine/Hybrid System - Cooling - "Engine Coolant (1NZ-FXE): Replacement"^ 2006 / 2007 Prius:Engine/Hybrid System - Cooling - "1NZ-FXE Cooling: Coolant On-vehicle Inspection"11. Clear DTCs.© 2012 Lexus, a division of Toyota Motor Sales, USA © 2016 ALLDATA, LLC. All Rights Reserved. Terms of Use (Version 2.0.13792)T-SB-0231-12November 29, 2012MIL "ON" DTC P1121Service Category
Engine/Hybrid SystemSection
CoolingMarket
USAZoom and Print Options ApplicabilityIntroductionSome customers with 2004 - 2007 model year Prius vehicles may experience a MIL "ON" condition with Diagnostic Trouble Code (DTC) P1121, Coolant Flow Control Valve Position Sensor Stuck. Use the repair procedure below to address this condition.Production Change Information Zoom and Print Options This bulletin applies to vehicles produced BEFORE the Production Change Effective VINs shown. Zoom and Print Options Parts Information Zoom and Print Options Warranty Information Zoom and Print Options Required Tools & EquipmentRepair Procedure1. Check DTCs and confirm P1121 is present. Zoom and Print Options 2. Remove the engine under cover LH. Zoom and Print Options 3. Drain the engine coolant.Refer to the Technical Information System (TIS) applicable model and model year Repair Manual:^ 2004 / 2005 Prius:Engine/Hybrid System - Cooling - "Engine Coolant (1NZ-FXE): Replacement"^ 2006 / 2007 Prius:Engine/Hybrid System - Cooling - "1NZ-FXE Cooling: Coolant: On-vehicle Inspection" Zoom and Print Options 4. Mark the upper coolant hose (hose to heater core). Take note of the original location of all coolant hoses.5. Remove the electrical connector on the coolant flow control valve.6. Remove all three coolant hoses on the coolant flow control valve.7. Remove the coolant flow control valve from the vehicle body.8. Install the replacement coolant flow control valve in reverse order of removal.
Expert:  Chad Farhat replied 1 year ago.

the P1121 has TSB on it i send it to you to read

have you flushed the coolant and you also need to check the circuit for the cht sensor ,

checked all fuses inside fuse box & outside

these codes are fixable

Customer: replied 1 year ago.
thanks for that. What is the cheapest way to go about fixing this short of doing it myself?
Expert:  Chad Farhat replied 1 year ago.

can you u give 2 minutes be right back .

thank you ,

and i will give you some ideas

Customer: replied 1 year ago.
Hello?
Expert:  Chad Farhat replied 1 year ago.

1-purchase the coolant flow control valve

2-CHS (Tank Outlet Temp Sensor

Call the local Toyota Dealer , ask for parts department , give him your vin#, ask hime how much for the 2 parts 1-Flow control valve 2- The CHS sensor

Expert:  Chad Farhat replied 1 year ago.

find a local shop to change

as far as labor , it is a an 2.5 hrs job & having a lift be easier

unless the problem is with circuit to the CHT sensor, then you need to find either a bad wire or a bad ecu not sending ground to it

Expert:  Chad Farhat replied 1 year ago.

after the dealer give u part # ***** to ebay and see if u can find them cheaper , just enter the part number on ebay search bar

Expert:  Chad Farhat replied 1 year ago.

also ask to have the coolant flushed

Expert:  Chad Farhat replied 1 year ago.

hopefully it is the sensor , at my shop 90% of time it is the CHT sensor, but sometimes its a short or ecm , its rare , but i seen it happened . finding the short could take hours of troubleshoot but hopefully that is not your case .

Hope I was helpfull to you ,Let me know if you need anything esle on it

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Thank You

Chad Farhat ( aka -Customer)
ASE Certified Technician