DTC: P155B-00
Manufacturer: Nissan
Component: Engine Control Module (ECM) / Variable Valve Timing (VVT) system
Typical Description: "Electric Intake Valve Control Actuator Circuit Performance / Bank 1" or similar (depending on model).
If you have this code, check your negative battery terminal first. If a mechanic recently changed your battery and did not reinstall the factory sensor correctly (or damaged it), that is the cause. If the terminal looks stock and undamaged, replace the Battery Current Sensor.
The Nissan P155B-00 fault code typically refers to a malfunction within the Selective Catalytic Reduction (SCR) system, specifically involving the Reductant Heater Control Circuit or a general SCR system fault. This code is most commonly seen in modern Nissan diesel vehicles, such as the Navara NP300, that utilize AdBlue (Diesel Exhaust Fluid) to meet strict emission standards. What Does P155B-00 Mean?
The "P155B" prefix indicates a manufacturer-specific code rather than a generic OBD-II code (which usually starts with P0). In the context of Nissan’s SCR system:
Reductant Heater Failure: The engine's computer (ECM) has detected that the heater responsible for keeping the AdBlue fluid from freezing or maintaining its operating temperature is not performing correctly.
Circuit Malfunction: The "-00" suffix often suggests a general failure or a "no sub-type" information status, meaning the circuit is either open, shorted, or the heater itself has failed. Common Symptoms
When this code is triggered, you may notice one or more of the following:
Check Engine Light (MIL): The most obvious sign is the dashboard warning lamp.
AdBlue/DEF Warning: A message stating "SCR System Fault" or "AdBlue Error" may appear.
Engine Derate (Limp Mode): To prevent excessive emissions, the vehicle may limit engine performance by up to 40% or cap the maximum speed. nissan p155b-00
No-Start Countdown: In severe cases, the vehicle may display a countdown of miles remaining before the engine will no longer start until the system is serviced. Common Causes
Faulty AdBlue Dosing Valve/Injector: The injector can become blocked by crystallized DEF, leading to circuit issues.
Damaged Wiring Harness: The SCR system components are located under the vehicle and are exposed to road debris, water, and heat, which can cause corroded or broken wires.
Defective Reductant Heater: The internal heating element within the DEF tank or the lines may have failed.
Poor DEF Quality: Using contaminated or old Diesel Exhaust Fluid can trigger SCR-related codes. Troubleshooting and Repair Steps
If you encounter the P155B-00 code, follow these diagnostic steps to identify the root cause:
Step 1: Inspect the AdBlue Injector. Locate the AdBlue injector on the exhaust pipe. Check for signs of white "crystal" buildup. You can sometimes clean a blocked injector by soaking the tip in warm water to dissolve the urea crystals.
Step 2: Check Wiring and Connectors. Perform a visual inspection of the wiring harness leading to the DEF tank and the dosing valve. Look for any corrosion or frayed wires that might be causing a short or open circuit.
Step 3: Test Component Resistance. Use a multimeter to check the resistance of the reductant heater and the dosing valve. Compare these readings against the factory specifications found in a Nissan Service Manual. If you have this code, check your negative
Step 4: Perform a Forced Reset. After repairs, the code often requires a "Hard Reset" using a professional-grade diagnostic scanner to clear the "SCR System Fault" and end any limp-mode conditions.
Note: SCR repairs can be complex due to the software integration. If cleaning the injector and checking the wiring does not resolve the issue, it is highly recommended to visit a specialist or dealer to ensure the ECM adaptives are properly reset.
It seems you're asking about the Nissan fault code P155B-00, which typically indicates a problem with the Glow Plug Control Module or its circuit in diesel models like the Nissan Navara , , or .
While I can’t find a published fictional story about this specific code, I can give you the "story" of what happens to a car when this code pops up—a classic tale of a cold morning and a stubborn engine. The Story of the Cold Start
It usually begins on a chilly morning. You turn the key, and instead of the usual quick purr, the engine cranks for a long time without catching. This is because the glow plugs—the tiny heaters that prep the combustion chamber for diesel—aren't getting the signal to warm up.
The Culprit: The Glow Plug Control Module has failed or lost communication.
The Conflict: Because the air inside the cylinders isn't hot enough, the diesel doesn't ignite properly. This leads to rough idling, white smoke from the exhaust, and eventually, the Check Engine Light glowing on your dash.
The Plot Twist: If you ignore it, the story gets expensive. Poor combustion from cold starts can lead to a clogged DPF (Diesel Particulate Filter), which can eventually put the car into "Limp Mode" to protect the engine. Technical Quick-Fixes
If you are looking for a solution to this "story," mechanics usually follow these steps: If you have this code
Check the Relay: Often, it's just a faulty glow plug relay that has burnt out.
Test the Harness: Inspect the wiring harness for corrosion or breaks, especially near the connectors.
Replace the Module: If the wiring is fine, the Glow Plug Control Unit itself may need replacing.
Note: If you actually meant P0155 (which is a very common O2 sensor heater code), that's a different story involving your exhaust and fuel efficiency.
Did you want the technical breakdown of how to fix this, or were you looking for a fictional narrative about a car breakdown?
Code Meaning: P155B-00
| Service | Estimated Cost (USD) | |---------|----------------------| | Diagnostic fee | $100 – $150 | | Coolant bypass valve (OEM) | $120 – $250 | | Coolant & supplies | $30 – $60 | | Labor (1.5 – 2.5 hours) | $150 – $300 | | Total at dealership | $350 – $650 | | Total at independent shop | $250 – $450 | | DIY cost | $150 – $300 |
Note: Prices vary by region and model year. V6 engines often require more labor due to tighter access.