Engine coolant indicator

One advantage us dealer tech's have over a week end warrior is that we have factory service repair information and have factory scan tool ,Tech 2 , to check data coming into the instrument cluster . Most of you probably don't even think about how that coolant temp infor shows up on the gauge , except by a coolant sensor !

High Temperature Indicator
The high temperature Indicator function handles the control of the Engine Temperature Gauge Display and the red High Temperature indicator. The Powertrain Control Module (PCM) reads the Coolant Temperature Sensor, filters the messages, and sends the coolant temperature to the instrument cluster via a Class 2 serial data message. The PCM monitors the coolant sensor in order to determine a fault. The PCM transmits the Class 2 serial data coolant temperature report messages to the instrument cluster for the temperature gauge display and for the high temperature indicator control.
The instrument cluster receives the engine temperature data in the Class 2 serial data message from the PCM. The instrument cluster converts this data into a temperature gauge pointer position which drives the gauge pointer. The instrument cluster also uses this data in order to determine the high temperature indicator control.
The Body Control Module (BCM) looks for the high temperature indicator Class 2 serial data report from the instrument cluster and triggers a chime when the indicator is ON.

Your best bet , take it to a qualified repair shop , rather then just replacing parts .

As with all engine codes there is no one solution fits all, here is the info on the code from the diagnostic material.
P0118 - Engine Coolant Temperature Circuit High Input
Possible causes - Low engine coolant level
- Engine Coolant Temperature (ECT) sensor harness is open or shorted
- Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
- Faulty Engine Coolant Temperature (ECT) sensor
- Faulty engine coolant thermostat P0118 Description The Engine Coolant Temperature (ECT) sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the Engine Control Module (ECM). The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

I think the engine coolant temp sensor or coolant thermostat has failed.

From the limited information you gave it sounds like your thermostat is stuck open.
The thermostat is a temperature operated valve that stops the coolant from flowing through the radiator until the engine warms up. I simple test is to drive for 5 minutes and then check the heater output. The temperature of the air from the heat vents is related to the coolant temperature in the engine. If the air from the vents is only slightly warm with the heater set on HIGH then change your thermostat.
Changing the thermostat on a 4 cylinder Camry is a fairly basic DIY job. Your friends at Autozone can fix you up with the parts (don't forget the gasket). You'll need to (partially) drain the radiator in the process. Probably a good time to change it. You can buy pre-mixed or get a gallon of "pure" and a gallon of distilled water from the grocery store and mix your own.

Hi,
it wouild appear from your description that the engine coolant sensor is developing values in excess of it's set parameters.

Having said that. I would check the connection to the sensor to ensure there is no high resistance, clean the connection anway, refit it, then have a local auto parts shop re-check the codes for you. If the code read-out remains the same. IIt would indicate a faulty coolant sensor.

Good luck.

Water Temperature Indicator Sender Unit
The water temperature indicator sender unit is installed on the engine into an engine coolant passage. The water temperature indicator sender unit reacts to the engine coolant temperature. Its resistance decreases as the engine coolant temperature increases.

Water Temperature Indicator Sender Unit Removal
CAUTION: Do not mix Standard (green) Coolant with Extended Life Coolant (orange). If mixing occurs, drain engine cooling system and refill with originally equipped coolant type. If this contamination occurs the service change interval on Extended Life Coolant will be reduced from 6 years/150,000 miles to 3 years/30,000 miles.

1. Partially drain engine cooling system as described.
   

1. Disconnect engine control sensor wiring (12A581) from water temperature indicator sender unit (10884) .
   

1. Remove water temperature indicator sender unit.
   

16502/P0118/000280 From Ross-Tech Wiki Jump to: navigation, search Contents [hide]

• 1 16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High
  • 1.1 Possible Symptoms
  • 1.2 Possible Causes
  • 1.3 Possible Solutions
  • 1.4 Special Notes

if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } 16502/P0118/000280 - Engine Coolant Temperature Sensor (G62): Signal too High Possible Symptoms

• Difficulties with starting a cold engine.
• Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
• RPM at idle is irregular.
• With all engine temperatures idle rpm will often vary between 900 - 1000 rpm.
• With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
• Bad acceleration during warm-up.
• Diesel Engines: Glow plug indicator may be on for a longer than normal time or at ambient temperatures where it shouldn't come on at all.

Possible Causes

• The electrical signal coming from G62 is too low
• Wiring and/or connections faulty (short circuit?)
• Engine Coolant Temperature Sensor (G62) faulty

Possible Solutions

• Check wiring and connections
• Check / Replace Engine Coolant Temperature Sensor (G62)

Special Notes

• In many cars between MY 1995-2002 the G2/G62 had a bad reputation for failing often. The original G2/G62 sensor is black and the improved replacements are green.

If you mean P0128, then this means that the engine's PCM detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine.

Check the following

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

The most likely cause would be a faulty thermostat

replace the sensor and or check the wiring socket going to the sensor

Complain to Toyota, they are fixing some of these car for free. Here is the explanation and the list of problem vehicles.

Oil sludge or black sludge is a solid or gel in motor oil caused by the oil gelling or solidifying, usually at temperatures lower than 100 degrees Celsius. Sludge can be a major contributor to Internal combustion engine problems, and can require the engine to be replaced, if the damage is severe. Sludge is usually caused by the presence of water in the oil, and can accumulate with use. Ways to minimize sludge production and accumulation includes performing frequent oil changes, using synthetic oil, and following the manufacturer's engine maintenance routine.
The following engines were reported by the Center for Auto Safety and/or their manufacturers to have a problem with sludge accumulation:

1996-2001 Toyota 3.0 L 1MZ V6

• August 1996-July 2001 Toyota Camry
• June 1998-May 2001 Toyota Camry Solara
• July 1997-May 2001 Toyota Sienna
• July 1996-May 2001 Toyota Avalon
• November 2000-July 2001 Toyota Highlander
• August 1998-July 2001 Lexus ES300
• January 1998-July 2001 Lexus RX300

1996-2001 Toyota 5SFE I4

• August 1996-July 2001 Toyota Camry
• June 1998-May 2001 Toyota Camry Solara
• August 1996-April 1999 Toyota Celica