Opel and Vauxhall Common OBD-II Codes: Astra, Insignia, Corsa, Mokka

Opel (sold as Vauxhall in the UK) is now part of Stellantis. Astra (J/K), Insignia (A/B), Corsa (D/E), and Mokka use a mix of GM-heritage ECOTEC engines and newer PSA-derived units. Understanding their OBD-II codes is important for UK and European owners.

1.6T A16LET / A16LES (Astra J, Insignia A): Turbo Issues

P0299 — Underboost

The 1.6 Turbo (A16LET, 170/180 hp) in Astra J OPC and Insignia is prone to:

• Intercooler inlet/outlet hose splits (after heat cycles)
• Diverter valve (DV) failure — common after 60,000–80,000 miles
• Boost solenoid (MAP solenoid) failure

Live Data:

• Boost Pressure Target vs Actual at 3,500 RPM WOT: expect 175–200 kPa
• Diverter Valve Position % on lift: should snap to 0% (closed)

P0171 — Lean Mixture (1.6T)

• Mass airflow sensor contamination (accessible under the air filter)
• Split intake hose between MAF and turbo inlet

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Z20NET / Z20LET ECOTEC 2.0T (Astra G/H, Vectra C): Older Turbo

The Z20NET (175 hp, Astra H/Vectra C 2.0T) and Z20LET (200 hp, Astra G/H OPC):

Common codes:

• P0101 — MAF: performance out of range (dirty or failed MAF)
• P0299 — Underboost (intercooler pipe, BOV)
• P0302 — Cylinder 2 misfire (coil pack failure — GM used early COP coils)

Coil pack P030X on Z20NET: GM ECOTEC coil-on-plug units are known to fail around 80,000–100,000 miles. Rotation test: swap coil from P0302 cylinder to another cylinder — if code follows = coil fault.

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CDTI Diesel (1.7 CDTi, 2.0 CDTi): Common Issues

2.0 CDTi (A20DTH / A20DTJ) — Insignia, Astra J

Code	Description
P0087	Fuel rail pressure below threshold
P0191	Fuel rail sensor: performance out of range
P2002	DPF efficiency below threshold
P0401	EGR insufficient flow
P0299	Variable geometry turbo: underboost

VTG (Variable Geometry Turbo) on CDTi:

• Turbo Vane Position % at idle: 80–90% (vanes nearly closed to build exhaust energy)
• During acceleration: 20–40%
• Sticking vanes from carbon = P0299

EGR cleaning: Carbon accumulates in EGR valve after 60,000–80,000 miles. Live Data: EGR Commanded % vs EGR Actual % — if > 10% difference = valve stuck.

1.7 CDTi (B13DTE / A17DTR) — Corsa, Mokka, Meriva

Smaller diesel with known issues:

• P0670–P0674 — Glow plugs (all 4 fail within the same mileage window — replace all at once)
• P2002 — DPF blocked (1.7 CDTi DPF particularly sensitive to short trips)

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Mokka X / Crossland X: GM/PSA Transition Models

Some models bridge GM and PSA technology:

Crossland X / Grandland X (PSA-based):

• EP6 THP 1.2T from PSA (same as Peugeot 208/2008)
• P0016, P0299, P0011 — same as Peugeot (see PSA guide)

Mokka X (2016+, GM-based):

• 1.4T (B14NEH) — ECOTEC
• P0420 — Catalyst below threshold (common at 80,000+ miles)
• P0011 — VVT over-advanced (OCV issue)

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FlexRide (CDC Suspension): Chassis Codes

Some Astra J/K and Insignia have FlexRide (Continuous Damping Control):

• C0040 — Wheel speed sensor: fault (also affects FlexRide)
• C1234 — CDC actuator: fault
• B2960 — CDC module: calibration required

After suspension or strut replacement → CDC calibration needed via OBD-II actuation test.

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IntelliLink / Navi 900: Infotainment Codes

Opel/Vauxhall infotainment issues usually show up as:

• U0184 — Lost communication with radio
• U0416 — Lost communication with central gateway
• B102D — IntelliLink: software corruption

Often resolved by battery disconnect or software re-flash at dealer.

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CDTi diesels (1.7 and 2.0 CDTi): typical problems

P0100 / P0101 — mass airflow sensor. On the 1.7 CDTi (Astra H, Zafira B) the MAF gets fouled by oil from the crankcase ventilation. Symptoms: a flat spot under acceleration and black smoke. Before replacing it, check MAF g/s at idle — the 1.7 should read roughly 20–24 g/s; anything under 15 means a dirty or dead sensor.

P0299 on a diesel is not the same fault as on petrol. Here the usual culprit is the turbo control valve or a leak after the intercooler. Check the post-intercooler hoses — they split along the seam.

P2453 — DPF pressure sensor. On the 2.0 CDTi the sensor lines clog with soot and feed the ECU a false picture. Cleaning the lines fixes roughly half the cases, without touching the filter itself.

Mokka X and Crossland X: the GM/PSA transition models

These sit apart: after Opel moved under PSA control they mix components from two platforms, and diagnostics behaves accordingly.

• PSA engines (1.2 PureTech, 1.5 BlueHDi) report codes in PSA format rather than GM. A generic ELM327 reads standard P-codes fine, but manufacturer codes need dealer software.
• The 1.2 PureTech has a well-known wet timing belt problem: the belt delaminates and debris blocks the oil pickup. The direct OBD warning is falling oil pressure (P0521) together with P0016 from lost cam timing.
• Mixed buses — on the Crossland X some modules sit on the PSA CAN and others on GM architecture, so U-codes between them appear more often than on a single-platform car.

Summary Table

Model	Engine	Top Codes
Astra J/H	1.6T A16LET	P0299 turbo, P0171
Astra H OPC	Z20LET 2.0T	P0299, P0302 coil
Insignia A	A20DTH 2.0 CDTi	P0087, P2002 DPF
Corsa D/E	1.7 CDTi B13DTR	P0671 glow plugs, P2002
Mokka X	1.4T B14NEH	P0011 VVT, P0420
Crossland X	EP6 THP 1.2T	P0016, P0299 (PSA)

Opel/Vauxhall key maintenance: replace CDTi glow plugs proactively at 80,000 miles (all 4), clean EGR valve at 60,000 miles, DPF care through regular motorway driving, and address VGT sticking with cleaning before it becomes P0299.