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M62 8-Cylinder Engine Coolant Temperature Sensor Replacing & Testing
 
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Pelican Technical Article:

M62 8-Cylinder Engine Coolant Temperature Sensor Replacing & Testing

Nick Czerula

Time:

2 hours2 hrs

Tab:

$60

Talent:

*****

Tools:

22mm wrench or 22mm deep socket, flathead screwdriver, digital multi-meter, jumper wires

Applicable Models:

BMW X5 Sport Utility (2000-06)

Parts Required:

Engine coolant sensor

Hot Tip:

Work with a cool engine

Performance Gain:

Remedy a check engine light or incorrect engine temp gauge

Complementary Modification:

Replace coolant at same time

The engine coolant temperature sensor is responsible for sending the temperature of the engine to the DME and the instrument cluster. It is a four wire sensor, with two separate circuits, one for the instrument cluster and one for the DME. If you have a coolant sensor fault code stored in your DME and your engine isn't running right, I suggest replacing the sensor before digging too deep. You may also have an inaccurate temperature gauge in your instrument cluster. This can also be from a faulty sensor.

In this article, I'll go over the steps involved with replacing and testing the engine coolant temp sensor on the BMW X5 with an M62 8-cylinder engine.
Figure 1

In this article, I'll go over the steps involved with replacing and testing the engine coolant temp sensor on the BMW X5 with an M62 8-cylinder engine. Be sure to work with a cool engine. The coolant temp sensor is located at the front center of the engine on the left side of the throttle housing (yellow arrow).

First we have to remove the intake air duct that runs from the throttle housing (yellow arrow) to the mass air flow sensor (green arrow).
Figure 2

First we have to remove the intake air duct that runs from the throttle housing (yellow arrow) to the mass air flow sensor (green arrow).

Working at the fresh air intake, remove four plastic rivets (green arrows).
Figure 3

Working at the fresh air intake, remove four plastic rivets (green arrows). Use a pair of pliers (inset) to remove the center rivet. Once all the center rivets have been removed, pull the duct up to detach from the vehicle.

Then lift the duct up on the left side while detaching it from the duct (green arrow) on the right side.
Figure 4

Then lift the duct up on the left side while detaching it from the duct (green arrow) on the right side.

Working at the mass air flow sensor, loosen the hose clamp using a flathead screwdriver (green arrow).
Figure 5

Working at the mass air flow sensor, loosen the hose clamp using a flathead screwdriver (green arrow).

Working at the throttle housing duct, loosen the hose clamp using a flathead screwdriver (green arrow).
Figure 6

Working at the throttle housing duct, loosen the hose clamp using a flathead screwdriver (green arrow).

Next, you will have to rotate the throttle-housing duct up toward the left side of the vehicle in the direction of the green arrow.
Figure 7

Next, you will have to rotate the throttle-housing duct up toward the left side of the vehicle in the direction of the green arrow. This will detach it from the mass air flow sensor. Once the duct is detached from the mass air flow sensor, pull the duct off the throttle housing. There are two small hoses you have to disconnect in the following step. Be careful not to damage them during this step.

Working at the bottom of the intake air duct, detach the plastic line by squeezing the release collar (green arrows) while pulling the line off the duct.
Figure 8

Working at the bottom of the intake air duct, detach the plastic line by squeezing the release collar (green arrows) while pulling the line off the duct. Then pull the vacuum hose (yellow arrow) straight off the duct to remove it.

Replacing Coolant Sensor: Then, disconnect the sensor electrical connector by pulling it straight off the sensor.
Figure 9

Replacing Coolant Sensor: Then, disconnect the sensor electrical connector by pulling it straight off the sensor. The connector is held on by two small tabs. If they will not release, use a small flathead screwdriver to release them.

Replacing Coolant Sensor: Now you can loosen the sensor.
Figure 10

Replacing Coolant Sensor: Now you can loosen the sensor. Use a 22mm open end wrench (green arrow) and loosen the sensor about a half turn. This should be enough to remove it by hand the remainder of the way. If you have a 22m deep socket, it can be used to remove the sensor as well (yellow arrow).

Replacing Coolant Sensor: Place a drain pan under the left front of your engine.
Figure 11

Replacing Coolant Sensor: Place a drain pan under the left front of your engine. You can drain the coolant. However I find very little leaks out during the procedure, but be prepared for some coolant to escape. Unscrew the sensor (green arrow) and remove it from the engine. Be sure to replace the metal sealing ring (yellow arrow) when replacing the sensor. Install the new sensor finger tight. Then tighten it using an open end wrench. Be careful. It is easy to over-tighten the sensor. Top up and bleed the cooling system. Then reassemble the engine bracket.

Testing Coolant Temp Sensor: 
Testing Coolant Temp Sensor: Using a BMW scan tool, check for fault codes.
Figure 12

Testing Coolant Temp Sensor: Using a BMW scan tool, check for fault codes. Our subject vehicle has signal code 123. When I checked the frequency of the fault, it was present 145 times. I am going to show you a few quick ways to test the coolant temp sensor using a scan tool, the instrument cluster and a digital multi-meter. Be careful not to short any wires or damage electrical terminals during testing. Using the steps mentioned earlier, disconnect the coolant temp sensor.

Testing Coolant Temp Sensor: This photo shows the coolant sensor electrical and electrical connector pins.
Figure 13

Testing Coolant Temp Sensor: This photo shows the coolant sensor electrical and electrical connector pins. To test the sensor, connect your volt meter across two of the terminals and take a resistance reading. At 60 degrees Fahrenheit you should have about 6.5k Ohms between terminals 1 & 2 and about 2.5k Ohms between terminals 3 & 4. Now insert the sensor into warm water, as the temp increases, resistance should decrease. Keep in mind, these are rough specs. I rarely test coolant sensors this way, mostly because they are either shorted or have an intermittent connection. I prefer to test the circuits back to the monitoring devices. If the circuits are good, I will replace the sensor. The electrical connector terminal pins are arrow color coded as follows: the blue arrow points to pin 1; the green arrow points to pin 2; the yellow arrow points to pin 3; and the red arrow points to pin 4.

Testing Coolant Temp Sensor: Jump Pin 1 and Pin 2 together while monitoring the instrument cluster.
Figure 14

Testing Coolant Temp Sensor: Jump Pin 1 and Pin 2 together while monitoring the instrument cluster. When the circuit is open, the temp gauge will read cold (blue arrow). When you jump the terminals together the temp gauge will read hot (red arrow).

Testing Coolant Temp Sensor: You can also test the voltage from the cluster to the sensor.
Figure 15

Testing Coolant Temp Sensor: You can also test the voltage from the cluster to the sensor. Pin 1 should have about 3.5 volts. Pin 2 should have about 0.1 volts.

Testing Coolant Temp Sensor: Jumping Pin 3 and Pin 4 together won't net the same results.
Figure 16

Testing Coolant Temp Sensor: Jumping Pin 3 and Pin 4 together won't net the same results. Once the terminals are jumped, clear the fault codes, then check the scan tool data. On a cold engine, compare engine and radio outlet temperature readings. They should be about the same, as shown here. The green arrow points to temperature. The yellow arrow points to voltage.

Testing Coolant Temp Sensor: You can also test the voltage from the DME to the sensor.
Figure 17

Testing Coolant Temp Sensor: You can also test the voltage from the DME to the sensor. Pin 3 should have about 5 volts. Pin 4 should have about 0.1 volts.

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Comments and Suggestions:
matt Comments: I mistook your M62 step-by-step instructions for instructions for an N62 engine. Please disregard or erase my comment. Thank you.
November 10, 2016
  Followup from the Pelican Staff: No problem. - Nick at Pelican Parts  
matt Comments: I am attempting to replace this part on a M62TUB44 engine in a 2005 Morgan Aero 8 after getting a coolant temperature error OBDII code.

There are two sensors under the intake manifold that connect to thermostat/water pump assembly, one on either side of centerline of the engine. Both have the same terminal end connector, but it appears in your photos that these plugs are different. Can you help clear this up? Both of my plugs look to be of the thermostat connector type. I can't find anything that looks like the plug in this tutorial.
Thanks a million!
November 6, 2016
  Followup from the Pelican Staff: What are you looking for? new connectors or sensors? I am not sure what you're asking me to help with. - Nick at Pelican Parts  

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Page last updated: Fri 12/9/2016 02:40:23 AM