[riry_jetta]

Dear All...

I have been driving my P38 for overlanding almost 4 years. All system works perfectly... But now, I have problem with the temperature. At first, I thought that there is a problem my engine cooling system. After I checked everything, there is no problem with cooling system. I checked the engine temperature with external temperature test, the engine temp is around 85°C... But the temperature gauge in the dashboard, after 15 minutes I ran the engine, the gauge showed high temp close max.

I have changed all coolant sensors, AMR 1425 and ETC 8496, and check all the wiring system, seems to me that there is no problem at all. I check with my scanner, no error, No fault, nothing.

Please help... Any advise or have the same problem?

Regards.

RJ

 

[riry_jetta]

how is your radiator cap?, what is the condition and or age of your radiator and thermostat, have you had any coolant work recently?

Radiator cap, thermostat and all pipe line are in good conditions... The engine runs normal in 80-85 °C. I'm looking for voltage range from temperature sender sensor to BECM to make sure the sensor works accordingly.

 

[riry_jetta]

If everything on the cooling system checks out ok then perhaps it’s the dash indicator that is faulty? Reason of this suggestion is because I once had faulty reading of fuel gauge. Found the problem to be the solenoid that drives the indicator needle. Resoldered the connection and all is well eversince.
Just an idea to check.
Wah… kemping di mana nih, Mas? Seru kayaknya… sayang saya belum ketemu/gabung teman-teman LR atau P38 di sini, Jogja.
salam,
AR

Yes... Now I'm trying get reference for valotage range from the temperature sender sensor send to BECM. If it is with in range, probably the cause of my problem is from the instrument cluster.

Ha ha ha.. Iya Mas.. Di daerah Cisarua, Jawa Barat. IG @perjalanan_wong_alas.

Salam kena..

 

[riry_jetta]

Does the gauge slowly creep up to maximum as the engine warms up or does it jump to maximum as soon as you start the car?

The gauge increase smooth and slowly like normal gauge. It reach maximum after around 12-15 minutes after the engine starts.

 

[riry_jetta]

The dash gauge is fine as long as you remember it is a compressed scale gauge so only shows between 60 and 120 degrees. You say you replaced the sender? ETC8496 is the one that feeds the ECU, while AMR1425 is the single wire gauge sender fitted to very early GEMS. It was changed for a different one with two wire connection not long into production as the original one is susceptible to errors if the engine ground is not good.

OK.. I'll check my ground cable than although if it is right, it's anomaly coz bad ground cable should cause lower.

 

[riry_jetta]

The gage in the dash is a dummy gage it's there to give you an idea of temperature..the only true way to get the temperature of your vehicle is a good quality external gage for example a single important system of your performance or 4WD vehicle in one gauge. They are able to display Oil Temp, Water Temp, Oil Pressure, Fuel Pressure, EGT, IAT, Boost, Transmission Temp, Differential Pressure, RPM, Speed, Dual Volts.

You can purchase these type of gages from all over the World so you have access to it in Canada

JRP 14in1 Digital OLED Multi Gauge Display v2.5 :: Buy Here

The JRP 14in1 OLED multi gauge display v2.5 is here, perfect for performance cars & 4x4, can display Boost, Oil & Water temp, EGT, Fuel & Oil pressure and more.

www.justraceparts.com.au

I use this one in my 4X4 F-250 years ago this is highly accurate as it comes from the OBD II port

ScanGauge2 Australian Version - Vehicle Data OBD2 Scanner

ScanGauge2 Australian Version. Features include more than 15 built-in OBD2 realtime engine data gauges. Trip, fuel consumption and cost gauges & logging. X-Gauges for transmission temperature, EGT, DPF soot and more. OBD2 code reader, 5 trip computers and performance monitor. 3 yrs Australian...

www.scangauge.com.au

I try to keep everything in standard. Other than that, to check more details, I use my computer scanner, portable scanner and others... Before, I never had problem like this.... Really makes me headache...

 

[riry_jetta]

I had the same issue with my '96 4.6 p38. Everything was running around 85°C but the temp gauge was in the red. It would jump up fairly quickly and we worse at night.

I figured out it was because I had a bad body earth from the battery, and the gauge would be worse at night because I would have the lights on draining more volts.

Check your volt reading from your cigarette lighter and if it is around the 12.4 or lower then that would be your problem. My temp gauge would read hot if it dipped below 12.4v ish. Replace the +ve cable from the alternator to your battery with the thickest you can get, and replace your -ve cables from your battery to the body, suspension tower, and motor. The one causing me issues was the C-clip earthing the body between the battery and the fusebox as it had gotten loose.

OK... I'll do it today... Hope this might solve my problem ..

 

[riry_jetta]

I had the same issue with my '96 4.6 p38. Everything was running around 85°C but the temp gauge was in the red. It would jump up fairly quickly and we worse at night.

I figured out it was because I had a bad body earth from the battery, and the gauge would be worse at night because I would have the lights on draining more volts.

Check your volt reading from your cigarette lighter and if it is around the 12.4 or lower then that would be your problem. My temp gauge would read hot if it dipped below 12.4v ish. Replace the +ve cable from the alternator to your battery with the thickest you can get, and replace your -ve cables from your battery to the body, suspension tower, and motor. The one causing me issues was the C-clip earthing the body between the battery and the fusebox as it had gotten loose.

Problem solved... Thank you so much.... 🙏🙏

I check all my ground cable... Seems good... After I read your response, I check once again and more detail and I find out that my ground cable from battery to engine is almost broke. I can not see it because it's inside the insulation. After I replace it, everything fine now... If I check it from beginning, I don't have to buy those 2 new sensors....

But it's OK.. Thank you.... 🙏🙏

Almost 1 hour driving, temp gauge back to normal...

 

[riry_jetta]

I don't have that sensor in my car but from what I read in the article "..... The thermostat coolant temperature reading is sent to the ECM (Z132). The ECM compares the engine coolant temperature reading provided by the Ect sensor with the thermostat coolant temperature
reading. If the two temperature readings are not within the pre–set limit, an On–Board Diagnostic (OBD) code will be generated.
Listed below are the OBD fault codes.
NOTE: Depending upon the engine operating conditions (i.e. coolant temperature at engine start) a fault may be indicated by the ECT sensor first, before the thermostat monitoring sensor (X336).

CDTKA P1117 - Thermistor reading below -33-C (-27-F)
CDTKA P1118 - Thermistor reading above140-C (284-F)
CDTHM P0126 - Difference between radiator coolant temperature and engine coolant temperatures too small On detection of a thermostat monitoring sensor fault the ECM (Z132) will default to the ECT sensor signal.

Try this step :
1. Check your wiring sensor (physical, resistance and possibility short to ground)
2. Check all resistance value of the sensors.
3. Connect ground to temp sender wire to make sure the warning light gauge is working.
4. Connect the to wires of temperature sensors (ECT and X336) using resistor 500 ohm. Just to make sure the gauge is working.

Hopefully this can help you to solve the problem.

🙏🙏