{
    "lazyNodes": false,
    "abFitnotesFlag": false,
    "abCrawlReviews": false,
    "productOptionsCookie": false,
    "orderDelayFlag": false,
    "skipSessionCookie": false,
    "covidMessage": false,
    "fullTitleCookie": false,
    "nrLoggerCookie": false,
    "checkoutReviewCookie": false,
    "productOptionSeqCookie": false,
    "maintenanceFlag": false,
    "bufferETACookie": false,
    "multiShippingDiscountFlag": false,
    "newFitmentFlag": false,
    "surveyOptInFlag": false,
    "crossSellFlag": false,
    "skuMappingFlag": false,
    "paySplitCookie": false,
    "callDisableFlag": false,
    "zipPaymentFlag": "u",
    "hassleFreeReturn": false,
    "lifetimeReplacement": false,
    "cpn_off": false
}
1999 Honda Civic

1999 Honda Civic Coolant Temperature Sensors

Refine by:
See All

Shop Catalog

Showing 1 - 15 of 16 results
Display item:
15
30
45
Sort by:
Coolant Temperature Sensor, Blade Type, Female Connector, 2-prong Male Terminal -
Part Number: REPH316301
Guaranteed to Fit
$13.04
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L
  • 1999 Honda Civic HX 4 Cyl 1.6L
  • 1999 Honda Civic Value Package 4 Cyl 1.6L
  • 1999 Honda Civic EX 4 Cyl 1.6L
  • 1999 Honda Civic CX 4 Cyl 1.6L
  • 1999 Honda Civic Si 4 Cyl 1.6L
  • 1999 Honda Civic DX 4 Cyl 1.6L
  • 1999 Honda Civic GX 4 Cyl 1.6L
Product Details
Notes : Blade type; Female connector; 2-prong male terminalWarranty : 1-year Replacement unlimited-mileage warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Phthalates, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : TX37, 4257, 9342, 12029, 29342, 31244, 31641, 36426, 73947, 74257, 140714, 155984, 171238, 213718, 712500, 712703, 1580154, 1580524, 2111015, 009107511, 19189488, 25174240, 5862028470, 2CTS0121, 37870PJ5003, 37870PJ7003, 37870PK2005, 37870PK2015, 5S1468, 5S6235, 7N6, CTS042, EF0069, EF0168, HA1316395, MT0580, SK1580154, SU4006, SU4006VC, SU4208, SU7746, TS10180, TS5553, TS5553SB, TX37T, V26720002, WT5009, WTC1012Replaces OE Number : 4257, 9342, 12029, 29342, 31244, 31641, 36426, 73947, 74257, 140714, 155984, 171238, 213718, 712500, 712703, 1580154, 1580524, 2111015, 009107511, 19189488, 25174240, 5862028470, 2CTS0121, 37870PJ5003, 37870PJ7003, 37870PK2005, 37870PK2015, 5S1468, 5S6235, 7N6, CTS042, EF0069, EF0168, HA1316395, MT0580, SK1580154, SU4006, SU4006VC, SU4208, SU7746, TS10180, TS5553, TS5553SB, TX37T, V26720002, WT5009, WTC1012Product Fit : Direct FitReturns Policy : 30-Day Return Policy
Coolant Temperature Sensor, Sold individually
Part Number: MRD1TS1005
Guaranteed to Fit
$10.49
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L
  • 1999 Honda Civic HX 4 Cyl 1.6L
  • 1999 Honda Civic Value Package 4 Cyl 1.6L
  • 1999 Honda Civic EX 4 Cyl 1.6L
  • 1999 Honda Civic CX 4 Cyl 1.6L
  • 1999 Honda Civic Si 4 Cyl 1.6L
  • 1999 Honda Civic DX 4 Cyl 1.6L
  • 1999 Honda Civic GX 4 Cyl 1.6L
Product Details
Notes : Round Connector Shape; Female Connector Gender; 2 Terminal Quantity; Blade Terminal Type; Does not include Wiring HarnessWarranty : 12-month Motorad limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Promotions : Labor Day SaleRecommended Use : OE ReplacementProduct Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: DETS10180
Guaranteed to Fit
$30.99
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L Engine Des: D16Y7; GAS
  • 1999 Honda Civic DX 4 Cyl 1.6L Engine Des: D16Y7; GAS
  • 1999 Honda Civic HX 4 Cyl 1.6L Engine Des: D16Y5; GAS
  • 1999 Honda Civic Value Package 4 Cyl 1.6L Engine Des: D16Y7
  • 1999 Honda Civic EX 4 Cyl 1.6L Engine Des: D16Y8; GAS
  • 1999 Honda Civic CX 4 Cyl 1.6L Engine Des: D16Y7; GAS
  • 1999 Honda Civic GX 4 Cyl 1.6L Engine Des: D16B5; CNG
  • 1999 Honda Civic Si 4 Cyl 1.6L Engine Des: B16A2; GAS
Product Details
Warranty : 1-year or 12,000-mile Delphi limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : REPH316301Product Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: WKP2111015
Guaranteed to Fit
$12.49
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic DX 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic HX 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic Value Package 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic EX 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic CX 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
  • 1999 Honda Civic GX 4 Cyl 1.6L MFI, Naturally Aspirated, CNG
  • 1999 Honda Civic Si 4 Cyl 1.6L MFI, Naturally Aspirated, GAS
Product Details
Notes : NewWarranty : 90-day Walker Products limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Recommended Use : OE ReplacementProduct Fit : Direct Fit
4-Seasons OE Replacement Coolant Temperature Sensor, Sold individually
Part Number: FS36426
Guaranteed to Fit
$19.99
Vehicle Fitment
  • 1999 Honda Civic All Submodels All Engines
Product Details
Notes : M12 x 1.5 thread size; Male fitting gender; Female connector gender; Round connector shape; (2) terminalsWarranty : 120-day 4-Seasons limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : 4-Seasons OE ReplacementRecommended Use : OE ReplacementProduct Fit : Direct Fit
Standard OE Replacement Coolant Temperature Sensor, Sold individually
Part Number: SITX37
Guaranteed to Fit
$15.99
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L
  • 1999 Honda Civic HX 4 Cyl 1.6L
  • 1999 Honda Civic Value Package 4 Cyl 1.6L
  • 1999 Honda Civic EX 4 Cyl 1.6L
  • 1999 Honda Civic CX 4 Cyl 1.6L
  • 1999 Honda Civic Si 4 Cyl 1.6L
  • 1999 Honda Civic DX 4 Cyl 1.6L
  • 1999 Honda Civic GX 4 Cyl 1.6L
Product Details
Warranty : 3-year or 36,000-mile Standard limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Standard OE ReplacementInterchange Part Number : REPH316301, 4257, 9342, 12029, 29342, 31244, 31641, 36426, 73947, 74257, 140714, 155984, 171238, 213718, 712500, 712703, 1580154, 1580524, 2111015, 009107511, 19189488, 25174240, 5862028470, 2CTS0121, 37870PJ5003, 37870PJ7003, 37870PK2005, 37870PK2015, 5S1468, 5S6235, 7N6, CTS042, EF0069, EF0168, HA1316395, MT0580, SK1580154, SU4006, SU4006VC, SU4208, SU7746, TS10180, TS5553, TS5553SB, TX37T, V26720002, WT5009, WTC1012Replaces OE Number : 4257, 9342, 12029, 29342, 31244, 31641, 36426, 73947, 74257, 140714, 155984, 171238, 213718, 712500, 712703, 1580154, 1580524, 2111015, 009107511, 19189488, 25174240, 5862028470, 2CTS0121, 37870PJ5003, 37870PJ7003, 37870PK2005, 37870PK2015, 5S1468, 5S6235, 7N6, CTS042, EF0069, EF0168, HA1316395, MT0580, SK1580154, SU4006, SU4006VC, SU4208, SU7746, TS10180, TS5553, TS5553SB, TX37T, V26720002, WT5009, WTC1012Product Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: Z8YV26720002
Guaranteed to Fit
$45.49
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L 4-Door, Non-ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic HX 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, Automatic CVT Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic Value Package 4 Cyl 1.6L 4-Door, Non-ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic EX 4 Cyl 1.6L 2-Door, 4-Wheel ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic CX 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic Si 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic DX 4 Cyl 1.6L 4-Door, Non-ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
  • 1999 Honda Civic GX 4 Cyl 1.6L 4-Door, 4-Wheel ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Thread Size: M12 x 1, 5; Plug (Connector): 2 Pins
Product Details
Warranty : 24-month or 24,000-mile Vemo limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Promotions : European Vehicle PartsInterchange Part Number : 37870PJ7003, 37870PK2005, 37870-PJ7-003, 37870-PK2-005, 37870-PK2-015, 48160P6K004, 48160-P6K-004, 5862028470, FDU1138, GTR210, MEK100070, MEK100120, 213718, 25174240, 37870-PJ5-003Replaces OE Number : 37870PJ7003, 37870PK2005, 37870-PJ7-003, 37870-PK2-005, 37870-PK2-015, 48160P6K004, 48160-P6K-004, 5862028470, FDU1138, GTR210, MEK100070, MEK100120, 213718, 25174240, 37870-PJ5-003Recommended Use : OE ReplacementProduct Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: Z8YV26720001
Guaranteed to Fit
$44.99
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L 4-Door, Non-ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic DX 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic HX 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic GX 4 Cyl 1.6L 4-Door, 4-Wheel ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic EX 4 Cyl 1.6L 2-Door, 4-Wheel ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic Si 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 5-Speed, Manual Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
  • 1999 Honda Civic CX 4 Cyl 1.6L 2-Door, Non-ABS, Front Wheel Drive, 4-Speed, Automatic Transaxle; Aftermarket Grade; Plug (Connector): 1 Pin
Product Details
Warranty : 24-month or 24,000-mile Vemo limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Promotions : European Vehicle PartsInterchange Part Number : 83420-87702, 83420-87702-000, 834209E12, 6553621201, 37750-PH2-004, 37750-PH2-014, 83420-877-020-0, 553621201, 5862028370, EDU1256, GTR184, PEL100230, 34850-70B10, 34850-70B10-000, 19022013, 213401, 91171831Replaces OE Number : 83420-87702, 83420-87702-000, 834209E12, 6553621201, 37750-PH2-004, 37750-PH2-014, 83420-877-020-0, 553621201, 5862028370, EDU1256, GTR184, PEL100230, 34850-70B10, 34850-70B10-000, 19022013, 213401, 91171831Recommended Use : OE ReplacementProduct Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: FAC73198
Guaranteed to Fit
$17.49
Vehicle Fitment
  • 1999 Honda Civic HX All Engines
  • 1999 Honda Civic GX All Engines
  • 1999 Honda Civic DX All Engines
  • 1999 Honda Civic CX All Engines
  • 1999 Honda Civic Value Package All Engines
  • 1999 Honda Civic EX All Engines
  • 1999 Honda Civic LX All Engines
  • 1999 Honda Civic Si All Engines
Product Details
Warranty : Facet limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 37870PK2005, 37870PJ7003, 5862028470, MEK100120, GTR210, 48160P6K004, MEK100070Replaces OE Number : 37870PK2005, 37870PJ7003, 5862028470, MEK100120, GTR210, 48160P6K004, MEK100070
Coolant Temperature Sensor
Part Number: GPD1711361
Guaranteed to Fit
$11.49
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic DX 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic HX 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic Value Package 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic EX 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic CX 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic GX 4 Cyl 1.6L CNG, With 2 Terminal; M12 X 1.5 Thread
  • 1999 Honda Civic Si 4 Cyl 1.6L GAS, With 2 Terminal; M12 X 1.5 Thread
Product Details
Warranty : 1 year GPD limited warrantyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Product Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: FAC73052
Guaranteed to Fit
$6.49
Vehicle Fitment
  • 1999 Honda Civic HX All Engines
  • 1999 Honda Civic GX All Engines
  • 1999 Honda Civic DX All Engines
  • 1999 Honda Civic CX All Engines
  • 1999 Honda Civic Value Package All Engines
  • 1999 Honda Civic EX All Engines
  • 1999 Honda Civic LX All Engines
  • 1999 Honda Civic Si All Engines
Product Details
Warranty : Facet limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Interchange Part Number : 37750PH2004, 37750PH2014, 6553621201, 3485070B10, 5862028370, PEL100230, GTR184, 3485070B10000, 553621201, 8342087702000, EDU1256Replaces OE Number : 37750PH2004, 37750PH2014, 6553621201, 3485070B10, 5862028370, PEL100230, GTR184, 3485070B10000, 553621201, 8342087702000, EDU1256
Beck Arnley OE Replacement Coolant Temperature Sensor, Sold individually
Part Number: 158-0154
Guaranteed to Fit
$37.49
Vehicle Fitment
  • 1999 Honda Civic LX 4 Cyl 1.6L
  • 1999 Honda Civic DX 4 Cyl 1.6L
  • 1999 Honda Civic Value Package 4 Cyl 1.6L
  • 1999 Honda Civic EX 4 Cyl 1.6L
  • 1999 Honda Civic CX 4 Cyl 1.6L
  • 1999 Honda Civic GX 4 Cyl 1.6L
  • 1999 Honda Civic Si 4 Cyl 1.6L
Product Details
Warranty : 1 year or 12,000-mile Beck Arnley limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Series : Beck Arnley OE ReplacementInterchange Part Number : REPH316301Product Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: WKP2121022
Guaranteed to Fit
$28.99
Vehicle Fitment
  • 1999 Honda Civic All Submodels All Engines
Product Details
Notes : (1) Connector Quantity; (2) Terminal Quantity; Blade Terminal Type; Round Connector Shape; Female Connector Gender; Male Terminal GenderWarranty : 90-day Walker Products limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Product Fit : Direct Fit
Coolant Temperature Sensor, Sold individually
Part Number: H195342
Universal Fit
$36.24
Product Details
Notes : Coolant temperature sensor TBI 4 bbl analog Pro-Jection systems digital 2 bbl Pro-Jection P/N 502-20Warranty : 90-day Holley limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Product Fit : Universal
Coolant Temperature Sensor, Sold individually
Part Number: H1953410
Universal Fit
$47.45
Product Details
Notes : Coolant temperature sensor for Holley EFI and commander 950 systemsWarranty : 90-day Holley limited warrantyQuantity Sold : Sold individuallyProp 65 Warning :

Warning SymbolWARNING: This product can expose you to chemical which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.

Product Fit : Universal
Page 1 of 2 | Showing 1 - 15 of 16 results

Top Rated Products

The part is great it fixed the problem with my car .
Hannah H.
VERIFIED PURCHASER

Popular Products

Helpful Automotive Resources

Where Is the CTS Located?
Where Is the CTS Located?A CTS with a poor connection at the wiring connector will cause the PCM to supply an overly rich fuel mixture. Meanwhile, a shorted CTS or one that has a low resistance will cause the PCM to supply an overly lean fuel mixture, resulting in drivability issues.
How Much Does a Radiator Fan Replacement Cost? Here’s What You Need to Know
How Much Does a Radiator Fan Replacement Cost? Here’s What You Need to KnowLabor costs for this type of replacement will usually range anywhere between $100 and $400. The exact cost will depend on factors, such as the type of vehicle you have and the rates applied in your area. You’ll also have to consider taxes and the cost of other related repairs. What
A Beginner’s Guide to Fuel-Injected vs. Carbureted Engines
A Beginner’s Guide to Fuel-Injected vs. Carbureted EnginesSitting on top of the intake manifold and beneath the air filter, the carburetor is responsible for mixing air and fuel before they get to the cylinders. The Principle of Carburetion
Tips For Replacing the Engine Coolant Temperature Sensor
Tips For Replacing the Engine Coolant Temperature Sensor Pro Tip: A quick way to check the ECT for accuracy is to let the vehicle sit overnight and check with a scan tool to see if
P00B6 Code: Radiator Coolant Temperature / Engine Coolant Temperature Correlation
P00B6 Code: Radiator Coolant Temperature / Engine Coolant Temperature CorrelationOn a 2015 Chevy Cruze, conditions for Running this DTC are as follows: DTCs P00B3, P00B4, P00B6, P0112, P0113, P0117, P0118, P0502, P0503 or P2610 have not been set.The vehicle has been OFF for greater than 8 hours before vehicle ON.The vehicle is ON, or the engine is running.The intake air temperature
Engine Coolant Temperature Sensor: Purpose, Location, and Failure Signs
Engine Coolant Temperature Sensor: Purpose, Location, and Failure SignsThe ECT sensor is a high-authority sensor whenever the engine is cold because ignition timing is tailored according to the engine coolant temperature. It also provides input for idle air control (IAC) position, oxygen sensor closed-loop status, on/off times for the canister purge, and idle speed.