Gaz 25 P1642 Engine Trouble Code
What is Gaz 25 P1642?
The Gaz 25 P1642 check-engine light can indicate issues ranging from minor (loose gas cap) to serious (catalytic converter failure). Professional diagnostic scanning at a dealer or shop will identify the exact cause and required repairs.
P1642 on the Gaz 25
Gaz 25 models produced in the mid-cycle refresh years show a statistical uptick in P1642 occurrences linked to the variable valve timing (VVT) actuator. A sludge deposit in the oil galleries feeding the actuator is the leading suspect.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Gaz 25 |
| Brand: | Gaz |
| Model: | 25 |
| Code: | P1642 |
P1642 Gaz 25 Symptoms
Check Engine Light
Illuminated Gaz 25 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Gaz 25
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Gaz 25
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 Gaz 25 P1642
Diagnostic Steps:
Check if fuel pump primes when key is turned to ON. Measure fuel pressure and verify bright white-blue spark at all plugs. Also verify mechanical timing alignment.
Repair Solution:
Power steering pressure switch monitors system operation. If pressure changes are not detected after calibrated speed transitions, this DTC sets. Verify PSP switch operation and check for circuit opens or shorts.
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.
Gaz 25 P1642 Repair Cost
Throttle body cleaning and idle relearn on the Gaz 25 for a P1642 diagnosis costs $60–$100 at an independent shop. If a full throttle body replacement is needed (rare), expect $250–$450 including programming the unit to the ECU.
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 Gaz 25
The Gaz 25 knock sensor shares its harness with the coolant temperature sensor. A corroded shared ground causes both sensors to report out-of-range values simultaneously, leading to misdiagnosis of P1642 as a knock sensor fault when the root cause is the shared ground splice.
DIY Repair Guide: P1642 on Gaz 25
Battery terminal cleaning on the Gaz 25 is a 5-minute job that resolves a surprising number of P1642 intermittents. Use a wire brush and a bicarbonate of soda solution to clean corrosion, then apply a thin coat of petroleum jelly to the terminals after refitting.
Preventing P1642 on the Gaz 25
Spark plug replacement at the manufacturer's interval — typically 30,000–60,000 miles depending on plug type — is the single most cost-effective preventive maintenance item for avoiding P1642 on the Gaz 25.
Frequently Asked Questions — Gaz 25 P1642
A: It depends on the severity. If the check-engine light is steady, it is generally safe to drive to a workshop within the next few days. If the light is flashing, pull over safely as soon as possible — a flashing light indicates an active misfire that can cause expensive catalytic converter damage within minutes.