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Daniel Wilson
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Category: Medium and Heavy Trucks
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Experience:  Owner at DJ Wilson
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2008 Isuzu NPR HD V8 Gas engine Here is the

Customer Question

2008 Isuzu NPR HD V8 Gas engine Here is the vin:4KLC4B1U38J801395
I bought the truck in April and the guy I bought it from said the transmission was rebuilt in February 2016. I have 4 transmission codes:
1. P0700 Transmission Control System (Malfunction Indicator Lamp Request) Confirmed
2. P0894 Transmission Component Slipping Confirmed
3. P0700 Tranmission Control System (Malfunction Indicator Lamp Request) Pending
4. P0894 Transmission Component Slipping PendingWhat do these codes mean and how can I fix them?Thanks Alex
Submitted: 2 months ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 month ago.

Hi Alex, My name is***** will be glad to try to help. Bare with me while I pull up these codes.

Expert:  Daniel Wilson replied 1 month ago.

P0894 is thrown when the input and output speed differ from the speed sensors. Check the oil for dark discoloration and burnt smell. Also check the filter and oil pan for fritction material and metal debris or sludge indicating an internal failure requiring disassembly and rebuild.

TSB Number:


NHTSA Number:


TSB Date:

June 1, 2010

Date Added to File:

April 5, 2010

Failing Component:

Power Train:Automatic Transmission


Isuzu (chevrolet/GMC): the transmission slips, will not shift, or may overheat. Technicians may find DTCsP0894 or P0218 stored either current or in history. These conditions may be caused by friction material debonding from the torque converter.

Let me know

Expert:  Daniel Wilson replied 1 month ago.

P0700 - OBD II Trouble Code

OBD II Fault Code

  • OBD II P0700

Fault Code Definition

  • Transmission Control System Malfunction

What does this mean?

The purpose of the automatic transmission is to match the engine's optimum power and torque characteristics to the driver's desired rate of acceleration and speed by auto-selecting different gear ratios or 'speeds' to power the wheels.

When the code P0700 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is seeing greater than a specified RPM difference between the rotational speed of the Input RPM Sensor and the Transmission Output RPM Sensor. This can occur during shifting or when driving at steady speeds in the same gear. It often implies that the transmission is slipping.


  • Check Engine Light will illuminate
  • Vehicle will not shift properly
  • Decrease in fuel economy
  • In unusual cases, there are no adverse conditions noticed by the driver
  • In some cases, there may be performance problems, such as dying when coming to a stop after driving on the freeway and/or misfire-like symptoms

Common Problems That Trigger the P0700 Code

  • Defective Shift Solenoids
  • Defective Engine Coolant Temperature Sensor
  • Defective Valve Body
  • Dirty transmission fluid that restricts the hydraulic passages

Common Misdiagnoses

  • Engine Misfire problem
  • Internal Transmission problem
  • Driveline problem

Polluting Gases Expelled

  • HCs (Hydrocarbons): Unburned droplets of raw fuel that smell, affect breathing, and contribute to smog
  • CO (Carbon Monoxide): Partially burned fuel that is an odorless and deadly poisonous gas
  • NOX (Oxides of Nitrogen): One of the two ingredients that, when exposed to sunlight, cause smog

P0700 Diagnostic Theory for Shops and Technicians
When diagnosing a P0700 code, it is important to record the freeze frame information and then to duplicate the code setting conditions with a test drive. Pay close attention to the engine load, throttle position, RPM, and road speed because a P0700 can be difficult to detect.

One should monitor the RPM input speed and compare that to output speed RPM on a smooth, flat surface after the vehicle is warmed up and the fuel system is in a closed loop. Monitor how the Converter Lockup Solenoid responds to an increased amount of throttle. The Lockup Solenoid duty cycle should go to 0 percent when the Throttle Position Sensor is above 40 percent and should return to 100 percent when the throttle is returned back to 15 to 20 percent when going 45 mph +. The duty cycle should go to 0 percent whenever the throttle is fully released or when the vehicle has decelerated below 30 MPH. The Lockup Solenoid duty cycle should go to 0 percent whenever the brake pedal is applied, regardless of speed.

When looking at the Toque Converter RPM versus the Input Shaft RPM, observe if the scan tool data has a Converter Slip Speed PID or Parameter Identification. This can be very helpful in the diagnosis of an intermittent P0700. If the Lockup System is functioning correctly, the Slip Speed value should never be above 50 RPM. Try gently depressing the throttle on a gradual incline above 45 mph. When doing this, the Slip Speed should not increase. If it does and the Lockup Solenoid duty cycle is 100 percent—meaning it is fully applying the converter clutch—then you know you have a slipping Converter Clutch.

If the Slip Speed stays steady but the transmission Output Shaft Speed starts to decrease (along with the MPH), then you know that you have an internally slipping transmission, usually caused by worn Clutch Packs or Sprag 1-Way clutches. If the Slip Speed remains very high and the Lockup duty cycle is 100 percent, then it is likely that the Solenoid is defective, because the duty cycle is reporting that the PCM is commanding the Lockup System to apply, but there is no change. Even with worn out Converter Clutches, there is always some kind of Slip Speed reading. It may go very high whenever the throttle is applied, but there should be some kind of a RPM reduction between the Converter Speed and the Input Shaft speed that verifies the Lockup Solenoid and PCM are trying to do their jobs.

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