The csd relay kicks and cut the current to the heater plugs and pump when i connect the upper temp sensor isuzu 4ja1, 2.5l turbo what could be the problem, pump and injectors are reconditioned?

I would look at the fan switch plug see if you plugged it back in. You can hear the switch click right before the fan kicks on. Open the hood start the car let it get to operating temp watch the fan make sure it kicks on. If not look at the wired plug that connects to the temp switch if its all secure but the fan doesnt kick on. Look for the relay fuse check it if good then the switch is bad.

where are you , this is a USA forum and we dont have KB here.
my guess, is car is in Africa or Australia?
2.5L engine> 4 cylinders. what engine, use real name of engine.
its diesel got that.
Fuel injections systems vary by country....so no country no joy , sorry but bet the 3 person ever to tell country there... "!!!!
so I answer non specifically...... do to that....
Diesel 101:"
does it run for short time on test fuel?, if yes engine is ok if it sounds ok. if not, then the engine is bad (compression checks)
(fuel in a spray bottle means test fuel) sprayed in to the air induction."basics"

filters are next,
fuel pressure tests. (on common rail very tricky this)
glow plugs, i check current on each plug wire. (a meter with amp clamp device, mag sensed current)
it must flow huge current here, if not the plug is dead. one or all.

is the system primed?

the relay to the glowplugs is also turned off when ehgine temps are still above cut in temps..try changing the glowplug relay and temp sensor in the same system..

Using your tatco code reader, select current data (real-time data) and select engine coolant temp sensor (ECT). Run engine to operating temperature (A/C off). Monitor the temp reading - when the temp reaches approx 204 deg farenheit, the fans should kick on, after the temp drops to approx 198 deg farenheit, the fans should turn off. The fans are controled by the ECM (Engine Control Module). The ECM controls the cooling fan relays.

Make sure your fuel pump is kicking on. You need to make sure the engine is getting gas. Check the filter, gas lines, and the injectors. Check all fuses, relays that go to fuel system. If you are getting gas to the engine, check for spark. Visually inspect the plug/coil wires, distributor cap, and rotor. Make sure your timing belt/chain is not broken. It could be the distributor, cam sensor, crank sensor, ecm. Anyone of these can be the problem. You need to start checking to see if you are getting gas and spark to eliminate what you can. If you have a question, just write me back. Thanks for choosing FixYa.

the temperature gauge range of movement is still considdered an acceptable range and depending what weather conditions and other loading on vehicle eg going up hill also while towing. But some things ive come accross like possibly the water pump, at higher speeds the impeller could be loose on shaft and with pressure it may not be turning at proper speed, I would replace the thermostat for saftey measures also, while you looked at the water pump. Check out the heater hoses and pipes that run behind the engine to the other side for leaks also. check connections of temp sender unit wire on thermostat housing(there are 2 sensors on it) its the smaller of the 2.the other one is for cold starts

hi errol,try loosening the highest hot hose clip,to vent any trapped air,(make sure the plastic bottle is full).
to test the fans, run a wire from the battery to the fan and if fans run then it could be the sensor or the relay.....relay cheapest.

if there is no power to the fuel pump check relays and fuses....UNDERHOOD FUSE & RELAY PANEL IDENTIFICATION Fig. 2: Underhood Fuse & Relay Panel Identification Courtesy of ISUZU MOTOR CO. Fusible Link Identification ? A - 80 Amp (1991-92 3.1L) ? A - 60 Amp Main-1 ? B - 30 Amp Main-2 ? C - 30 Amp (1993-94) ECM (3.2L) ? D - 30 Amp Condenser Fan (A/T Models) Relay Identification ? 1 - Headlight Relay ? 2 - A/C - Heater Relay ? 3 - Starter Relay ? 4 - A/C Compressor Relay ? 5 - Charge Relay ? 6 - Fuel Pump Relay ? 7 - ECM Relay ? 8 - Wiper Relay Fuse & Circuit Breaker Identification ? 1 - 15 Amp (1991) ECM, Fuel Injection System ? 1 - 15 Amp (1992-94 2.6L) ECM, Fuel Injection System ? 1 - 10 Amp (1992-94 3.1 & 3.2L) Heated Oxygen Sensor, Fuel Injection System ? 2 - 20 Amp (1991-92) Fuel Pump ? 2 - 20 Amp (1993-94 2.6L) Fuel Pump ? 2 - 15 Amp (1993-94 3.2L) Fuel Pump ? 3 - 10 Amp (1991) ? 3 - 15 Amp (1992-94) Turn Signal Lights, Hazard Warning Flasher Lights ? 4 - 10 Amp Horn, Door Locks ? 5 - Not Used (1991 3.1L) ? 5 - 10 Amp Charging System, Charge Warning Light WARNING: Always disconnect battery ground cable before servicing "high- current fuses. It is recommended that "high-current" fuses be replaced by a qualified technician. Page 1 of 2 FUSES & CIRCUIT BREAKERS -1994 Isuzu Rodeo LS? 6 - Not Used (1991) (1992-93 2.6L) ? 6 - 10 Amp (1992-94 3.1L & 3.2L) A/T Interlock System ? 6 - 10 Amp (1994 2.6L) Heated Oxygen Sensor, Fuel Injection System ? 7 - 20 Amp Heater/Air Conditioning Blower Controls ? 8 - 10 Amp Air Conditioner Compressor Controls ? 9 - 10 Amp Right Headlight ? 10 - 10 Amp Left Headlight © 2008 Mitchell Repair Information Co., LLC.

Underhood fuse block swap out relay #7 thats the ECM relay.
Ground Circuits Using a DVOM, touch negative voltmeter lead to a good ground. Touch positive voltmeter lead to each ground terminal. With vehicle running, voltmeter should indicate less than one volt. If reading is greater than one volt, check for open, corrosion and loose connection on ground lead. See ECM GROUND LOCATION table for ECM ground location.
Page 1 of 1 SYSTEM/COMPONENT TESTS - 2.6L EFI -1994 Isuzu Rodeo

You may have an air pocket in your system which some times happens.  One way to get rid of it is to take the upper hose off on the engine side,  fill your system with water until it runs out from your engine block, replace the hose, start your car turn you heater on and set to hi keep the radiator cap loose until the temp start to rise then close tight.  Once the air pocket had been remover you can drain some of the water from the radiator using the lower drain plug and add antifreeze.   

I own the same 3500 GMC 6.5 diesel truck with the same problem. We replaced the brain under the upper turbo hood and it fixed it pronto. No more shutoffs