BRAND NEW *OEM Quality* engine coolant temperature sensor to suit Mazda MX-5 NB 1.8L with BP5A, BP6J, BP-ZE and BP4W engines.

On an NB the usual complaint is a thermo fan that will not switch on at a track day or in traffic, with the gauge still reading normal. A new sensor restores correct fan and fuelling control. Metro delivery 1-2 business days from Melbourne.

TO SUIT

Fits the Mazda MX-5 NB and NB8C 1.8 litre roadster with the BP5A, BP6J, BP-ZE and BP4W engines. Most variants are covered to August 2003, with the 113kW BP4W running through to 2005. The compatibility table below shows the exact split.

FITMENT CHECK

Coverage for the BP5A, BP6J and BP-ZE stops at August 2003 in our application data. If you have a 2003 to 2005 NB, check the engine code before ordering.

OEM PART NUMBERS

KLK1-18-840
KLK118840

OTHER PART NUMBERS

VEMO: V70-72-0120-1
WALKER: 211-1117
MTE-Thomson: 4255
Goss: CS844
TCS125
CTS-030
TX85

PACKAGE INCLUDES

1 x engine coolant temperature sensor with 3-pin triangular plug and seal ring.

ABOUT THIS SENSOR

The BP relies on this sensor for cold enrichment and for switching the electric cooling fans. The dash gauge runs off a separate sender, which is why an MX-5 can show a perfectly normal gauge while the ECU is working from a wrong number.

That split catches people out. A car that overheats on track with a healthy looking gauge is a classic symptom, because the fans are being commanded by the sensor the gauge does not use.

COMMON SYMPTOMS OF FAILURE

Fault codes P0115, P0117, P0118 or P0125 stored
Cooling fans not switching on while the gauge reads normal
Temperature climbing on track or in stop-start traffic
Rough idle and hesitation during warm-up
Heavy fuel use and a rich exhaust smell
Hard starting when the engine is hot

[1998 - 2003] MAZDA MX-5 MKII (1.8L 4cyl BP5A/BP6J 103kW)
[2000 - 2003] MAZDA MX-5 MKII (1.8L 4cyl BP-ZE/BP6J 107kW)
[2000 - 2003] MAZDA MX-5 MKII (1.8L 4cyl BP6J 102kW)
[2002 - 2005] MAZDA MX-5 MKII (1.8L 4cyl BP4W 113kW)

How do I test a coolant temperature sensor?

The most common test is to measure the sensor resistance with a multimeter at a known coolant temperature and compare against the manufacturer resistance curve. A cold engine (20 degrees C) typically reads 2,000 to 3,000 ohms and drops to around 200 to 300 ohms at operating temperature (90 degrees C). An OBD2 scanner showing a fixed temperature reading that does not change as the engine warms up is also a strong indicator of sensor failure.

Can a faulty coolant temperature sensor cause my engine to overheat?

Indirectly yes. If the sensor reports a lower temperature than actual, the ECU may not activate the cooling fan at the correct time, allowing the engine to overheat. It can also suppress the dashboard warning light, meaning you may not be alerted until the engine is already at a dangerously high temperature. Replace a suspected faulty sensor promptly.

Do I need to drain the coolant to replace the sensor?

Not always - many coolant temperature sensors can be replaced quickly with minimal coolant loss if you work fast and have a replacement ready to thread in immediately. However on some vehicles the sensor location requires partial coolant drainage. Check the sensor position on your specific engine before starting. Always use fresh coolant when topping up after replacement.

What are the symptoms of a faulty coolant temperature sensor?

Symptoms include poor fuel economy, black smoke, engine overheating warning, incorrect temperature gauge reading, hard starting when cold, and rough idle. Fault codes P0115 to P0119 are commonly associated with coolant temperature sensor faults.

Is it safe to drive with a bad coolant temperature sensor?

A faulty coolant temperature sensor can cause the ECU to run rich fuel mixtures and prevent the cooling fan from operating correctly, risking engine overheating. Replace it promptly - it is a low-cost part that can prevent expensive engine damage.

How do I know if my coolant temperature sensor or my thermostat is faulty?

A faulty thermostat typically causes the engine to overheat or never reach operating temperature. A faulty coolant temp sensor causes incorrect gauge readings and running issues but the coolant itself may be at the correct temperature. An OBD2 scanner showing live coolant temp data helps distinguish between the two.

Are there two coolant temperature sensors on my vehicle?

Many vehicles have two sensors - one for the ECU (engine management) and one for the dashboard temperature gauge. They look similar but are not interchangeable. Check your vehicle's service manual or contact us with your vehicle details to confirm which sensor you need.

Identification
SKU	CCS93-6
Brand	Aftermarket OEM Replacement
Part Numbers
Part Number	CCS93
Reference OEM Number	KLK118840
Other OEM Numbers	KLK1-18-840, KLK118840
Related Part Numbers	CTS-030, TCS125, CS844, TX85
Trade Part Numbers	VEMO: V70-72-0120-1, WALKER: 211-1117, MTE-Thomson: 4255
Product Specifics
Product Type	SENSOR
Sensor Type	Coolant Temperature Sensor
Manufacturer Warranty	1 Year
Thread Size	M12x1.5
Spanner Size	19mm
Number of pins	3-Pin
Connector Shape	triangular
Supplementary Article Info	with seal ring
Housing Colour	Grey
Mounting Type	Threaded
Compatible Makes	Mazda
Fitment Type	Direct Replacement
Other Details
Note	3-pin triangular plug, M12x1.5 thread, 19mm spanner
Unit Of Measure	ea