Isuzu D-Max 2012 factory workshop and repair manual download pdf

The Isuzu D-Max is a pickup truck built by automaker Isuzu since 2002. It shares the exact same system with some General Motors (GM) mid-size trucks in the United States as the Chevrolet Colorado, GMC Canyon and Isuzu i-Series. The Chevrolet Colorado name is additionally used to a rebadged variation of the D-Max in the Middle East and Thailand, although not identical to the American version. The original D-Max is sold alongside the Chevrolet Colorado in the Thai market in which they are both built. In Australasia between 2003 and 2008, the D-Max was marketed as the Holden Rodeo, but has since been relaunched as the Holden Colorado. The Isuzu D-Max itself was additionally introduced in Australia during 2008, selling alongside the Holden offering. in the United Kingdom, the D-Max is offered there as the Isuzu Rodeo.

Julie Beamer, director of GM Chile announced on March 5, 2008 to their workers of the only remaining automobile factory in Chile would close on July 31. To that day, the only product currently on production on that factory was the Chevrolet D-Max. The information came little after Hugo reduced the import quota for cars in Venezuela, the main export market of Chilean-made Chevrolet D-Max, but GM Chile said on its official statement that the reason behind the end of manufacturing in Arica were the lack of favourable conditions for vehicle production in Chile, and the stiff competition from many other carmakers and countries on Chile's car market.

The Thai-market Colorado is smaller than the North United states model of the exact same name and almost unrelated. In belated January 2006, Chevrolet introduced a G-80 differential lock system as elective for most Colorado trim levels. This feature is not available on the D-Max. The Thai-market Colorado received a minor redesign in late 2007.

Late first quarter of 2008, Chevrolet additionally introduced Colorado 4x2 2.5 with diesel dual fuel system via CNG tank. Switchable between diesel (65) and compressed natural gas (35) as the separated aspect (65:35); moreover additionally can use diesel purely as well. Biodiesel B5 is also acceptable. Location of tank is on the bed behind cab. Available for 2 cabstyles.

In March 2011, Chevrolet revealed the prototype version of all-new Colorado at Bangkok Motor Show, not related anymore to D-Max, shown as Extended cab with rear access system, and some of high-tech stuff, In June 2011, Chevrolet revealed crew cab in adventure concept at Buenos Aires, Argentina (this car also shown at Frankfurt Auto Show on September, 2011), and in July 2011, a Holden version of crew-cab version concept car got its premier at Australian International Motor Show, but the interior of this vehicle looked like manufacturing models any more than 2 concepts before.

In September 9, 2011, General Motors (Thailand) are opening the diesel engine manufacture plant, to make the "Duramax" engine, as the VM Motori rebadge engine (same as old 2-liter diesel Captiva) with 2.5 or 2.8-liter, manual and 2WD, automatic or 4WD. New 2012 Isuzu D-MAX Pickup Truck is actually the Chevy Colorado's Asian Twin.

Isuzu has long abandoned the U.S. Passenger and truck marketplace but it continues to have strong ties with General Motors, which was once its primary stockholder. In 2011, the Japanese automaker revealed its all-new D-MAX pickup truck, which was designed in cooperation with GM and is a sibling model to the 2012 Chevrolet Colorado. Albeit on separate occasions, both pickup truck models were presented in Thailand. On the outside, the new 2012 D-MAX qualities different front and back end styling treatments as well as bespoke trim parts, while inside, the changes over the Colorado are limited to the color options and the instrument panel. The body-on-frame Isuzu D-MAX launches in Thailand with three turbodiesel engines, including a pair of 2.5-liter units producing 115HP and 136HP, and a larger 3.0-liter powerplant with 177-horses.

Isuzu D-Max 2007-2012 Factory Service Workshop Manual

Safety first (read this): work in a well‑ventilated area, no sparks/open flame, wear eye protection and nitrile gloves, have a fire extinguisher nearby. Relieve rail pressure and disconnect the battery before touching fuel lines. Follow the Isuzu service manual torque values and sealing part numbers.

Ordered procedure with theory and how the repair fixes the fault

1) Symptom & diagnosis (theory)
- Common-rail diesel rail problems show as hard starting, long crank, rough idle, loss of power, black smoke, injector misfires, fuel smell, visible leaks, or fault codes (rail pressure sensor, low rail pressure, injector circuit faults).
- The rail is a high‑pressure manifold that stores fuel at the common-rail pressure set by the high‑pressure pump and controlled by the pressure regulating valve and engine ECU. Each injector seals into the rail; leaks or bad sensors cause pressure loss, air ingestion or incorrect sensor feedback → poor injection timing/quantity → the symptoms above.
- Confirm with scanner: read rail pressure live data vs commanded pressure, watch for pressure drops during cranking or load. Visual check for external leaks.

2) Prepare and depressurize (theory + steps)
- Theory: the common rail holds very high pressure even when the engine is off; relieving pressure prevents spray/serious injury.
- Steps: disconnect battery negative. Remove fuse/relay for fuel pump/ECU prime circuit to prevent pump operation. Use the pressure-relief procedure in the manual: either use a fuel-pressure test port (Schrader) to bleed down to zero with a gauge attached, or carefully loosen a low‑pressure fitting downstream into a catch container to let pressure escape. Confirm gauge reads zero.

3) Access and mark components
- Theory: keep correct injector/line order and avoid mixing connectors to preserve calibration.
- Steps: remove engine cover/intake components as required. Label injector electrical connectors and high‑pressure lines so each returns to its original port. Unclip wiring harness and remove any obstructing brackets.

4) Remove low-pressure feed and return lines
- Theory: drain and isolate the low‑pressure side before disturbing the high‑pressure rail to avoid spills.
- Steps: loosen and remove low‑pressure supply and return lines to the rail. Cap lines immediately and catch fuel.

5) Remove high‑pressure lines and sensors
- Theory: high‑pressure lines must be removed without damaging flare nuts or line integrity.
- Steps: carefully loosen the high‑pressure feed from the rail (use proper flare-nut spanner). Unplug / remove the rail pressure sensor (and any pressure relief valve or bleed screw). Cap/tape openings to keep contamination out.

6) Unbolt and withdraw the rail
- Theory: the rail is mounted to the head and holds injector tips sealed by O‑rings/washers. Removing it exposes injector seats and seals.
- Steps: remove rail mounting bolts in the recommended sequence. Pull the rail straight off; some installations remove the injectors with the rail, others leave injectors in the head — follow the D‑Max configuration. Inspect injector O‑rings and sealing washers for damage.

7) Inspect and replace seals/components
- Theory: most common rail faults are due to failed injector O‑rings, crushed copper washers, cracked rail, or a faulty pressure sensor/regulator. Air ingress or external leaks usually come from seals.
- Steps: replace all injector O‑rings and copper crush washers with new OEM parts. Replace rail pressure sensor and any pressure relief valve if suspect. Inspect the rail for cracks/corrosion; replace the rail if damaged. Clean the injector bores and sealing surfaces—no debris allowed.

8) Reassemble with correct lubrication & torque
- Theory: new seals must be lubricated to avoid tearing; bolts must be torqued to prevent leaks or distortion.
- Steps: lightly lubricate new O‑rings with clean diesel or assembly lube, seat injectors correctly, fit new washers, place rail and tighten mounting bolts in sequence to the specified torque (use manual specs). Reconnect high‑pressure lines finger-tight then final torque with flare-nut spanner. Refit pressure sensor and low-pressure lines.

9) Prime and bleed air from the system
- Theory: air in the fuel system causes poor pump operation and low rail pressure; priming expels air and allows pressure to build.
- Steps: reinsert fuel pump fuse/relay but keep battery disconnected? (Better: reconnect battery, use ECU priming mode or turn key to ON several times to run the lift pump priming cycles.) Operate the electric priming (or crank with injector fuses removed in short bursts) until fuel reaches the rail and gauge shows normal priming pressure. Check for leaks.

10) Pressure verification and calibration
- Theory: you must confirm actual rail pressure matches commanded values and that sensor readings are correct.
- Steps: connect a calibrated rail pressure gauge and scan tool. Start engine and observe rail pressure at idle and under commanded conditions. Compare sensor voltage/live data to gauge. If pressure is stable and within spec, clear codes.

11) Final checks and road test
- Steps: inspect all fittings for leaks after start and under drive. Check for drivability improvement (smooth idle, restored power). Re-scan for stored/active faults. Re-torque fittings after a short test run if required by manual.

How the repair fixes the fault (summary)
- Replacing damaged O‑rings/washers and reseating injectors restores a leak‑tight hydraulic connection so the high‑pressure pump can build and maintain required rail pressure. That fixes symptoms caused by pressure loss or air ingestion (hard starts, rough idle, loss of power).
- Replacing the rail pressure sensor or regulator fixes incorrect feedback/control, allowing the ECU to command the correct supply pressure and correct injector metering.
- Replacing a cracked rail removes an uncontrolled leak path and any associated loss of pressure.
- Cleaning seats and re-torquing prevents micro-leaks and ensures consistent injector timing/quantity across cylinders, restoring combustion balance.

Testing to confirm repair
- Use a scan tool to monitor rail pressure vs commanded, run a leak-down test (observe pressure decay with engine off), inspect all joints for fuel seepage, and verify absence of related fault codes.

End.
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