Nsu 1200 P1642 Engine Trouble Code
What is Nsu 1200 P1642?
When Nsu 1200 P1642 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
P1642 on the Nsu 1200
The Nsu 1200 uses a dual-port fuel injection architecture that is sensitive to ethanol content variations. When E10 fuel is substituted with E5, or vice versa, the fuel trim corrections can cross the DTC threshold and store P1642 in the ECU.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Nsu 1200 |
| Brand: | Nsu |
| Model: | 1200 |
| Code: | P1642 |
P1642 Nsu 1200 Symptoms
Check Engine Light
Illuminated Nsu 1200 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Nsu 1200
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Nsu 1200
Increased Emissions
Failed emissions test due to P1642
P1642 Code Structure
Understanding what each digit means in the P1642 powertrain trouble code:
| P | 1 | 6 | 4 | 2 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Temperature Sensor B Circuit Range/Performance | Injection Pump Fuel Metering Control 'B' High | Glow Plug/Heater Circuit 'A' Malfunction |
How to Fix Nsu 1200 P1642
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
P1642 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
Nsu 1200 P1642 Repair Cost
Intercooler hose replacement on turbocharged Nsu 1200 models costs $120–$250 per section. A boost-leak smoke test ($50–$80) is the definitive diagnostic method and will pinpoint exactly which hose or connection is at fault before any parts are ordered.
P1642 Description
P1642 engine trouble code is related to Glow Plug/Heater Circuit 'A' Malfunction.
Main Cause
The primary reason for P1642 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.
Common P1642 Misdiagnosis on the Nsu 1200
The Nsu 1200 is frequently taken to workshops for a P1642 fault where the technician replaces the throttle position sensor (TPS). In a significant proportion of cases, the root cause is a loose or cracked vacuum hose downstream of the throttle body that should have been found in a basic visual inspection.
DIY Repair Guide: P1642 on Nsu 1200
Replacing the oxygen sensor on the Nsu 1200 requires an O2 sensor socket (22mm or 7/8") and penetrating oil applied 24 hours in advance. On vehicles over five years old, the sensor threads often corrode into the bung; heat from a propane torch (briefly applied) is usually sufficient to free them.
Preventing P1642 on the Nsu 1200
Inspecting the Nsu 1200 wiring harness conduit grommets annually — especially the floor pan grommet — costs nothing and takes 10 minutes. Catching moisture ingress early eliminates the most common electrical trigger for P1642 on this model.
Frequently Asked Questions — Nsu 1200 P1642
A: Temporarily clearing P1642 can help determine whether it is intermittent or persistent, but it does not fix the underlying fault. The code will return if the problem is still present. Do not clear codes just before an emissions test without a proper drive cycle.